San Pedro de Atacama
San Pedro de Atacama is a town in Northern Chile. It's a very popular destination among Chilean tourists and international visitors alike. Visitors come in large numbers, to use the town as a stepping stone to the amazing landscapes around it. Most attractions are part of the Los Flamencos National Reserve, perhaps Chile's most varied and amazing national park. Prices in any of the laid back bars and restaurants fare well against Santiago's (Chile's Capital). Still, it's a fairly expensive location, as it's one of Chile's three most popular destinations, along Torres del Paine and Easter Island.
Buses connect San Pedro with Salta and Jujuy in Argentina, as well as the rest of Chile. Several buses per day connect the town with Calama, operated by TurBus and other carriers (Frontera del Norte, Atacama 2000, and Intertrans). The trip takes about 1 hour and 20 minutes, costs 2.500 pesos (USD 5). Other buses from TurBus travel to Antofagasta (4 hours, $6000), Iquique, Arica (12 hours, 22.000 pesos), and Santiago. There are also trips from Uyuni, in Bolivia, and Calama. Bus passes are available from the Green Toad Bus  which allow you to travel to San Pedro from Argentina, Brazil, Peru, Bolivia and the rest of Chile.
As of March 2014, the following are the schedules from Geminis and Pullman (which have the same prices for their routes at around $40-50 USD but different offices sell their tickets in bus station so ask at both for timing and price comparison): Mo, Th, Sa, Su at 7am from Salta, Jujuy at 8:45am, Purmamarca at 10:00am but usually earlier, San Pedro at 4pm but usually late. San Pedro to Calama leaving 4pm, arriving 6pm and continuing onwards to arrive at Antofagasta at 9pm, Iquique at 5:30am the next day and Arica at 6am (possible changes of bus involved with Pullman). Mo, Tu, Th, Sa, Su from Arica to San Pedro, leaving Arica at 9:30pm, Iquique at 11:10pm, Antofagasta at 5am, Calama at 8am and arriving in San Pedro at 9am-9:30am. The bus from San Pedro leaves at 9:30am (usually later) and then continues to Purmamarca for 6:50pm arrival, Jujuy at 7:50pm, and Salta at 9:30pm.
No airlines fly direct to San Pedro. The nearest commercial airport is Calama. Three airlines serve Calama: LAN, Sky Airline and PAL. Most flights are direct, and connect Calama with Santiago, but a few also fly to Antofagasta and Iquique. A two-way ticket can be had for as little as USD 120, but it must bought at least a month beforehand, and these flights usually leave either very early in the morning, or quite late in the evening. From Calama to San Pedro is about 90 minutes by bus.
At the Calama airport you may rent a car. Car rentals are fairly expensive, however, for Calama is Chile's largest mining hub, and therefore rentals offer mostly medium pick-up trucks. You will need an international driving permit if you're not Argentinian or Chilean. Rentals are cheaper in Antofagasta, but the drive to San Pedro is long (about four hours). Most popular destinations are fairly easy to reach with a good map, but driving high in the Andes should not be undertaken by beginners in the area! The roads are often in terrible condition, not signaled at all, there's no cell phone signal, and acute mountain sickness is a real threat. Getting stuck in the less-traveled roads of the "altiplano" can be a death sentence, since some aren't used at all, and see perhaps a car every two months.
Always travel with a full tank, since the only gas station in the area is in San Pedro. You can find illegal fuel vendors in some of the smaller towns, like Toconao, but they charge outrageous prices. Check the condition of all tires, even the spare; flat tires aren't at all unusual on the many dirt roads that lead to points of interest.
Chile is well-known as a hitchhikers paradise. Getting to Calama from any other point in the country is simple enough, but reaching San Pedro is a bit trickier. The best chances are to be had at the Topater monolith ("Monolito de Topater"). From there, walk south, beyond the underpass, and hitch a ride to town. You might have to wait for a while, but traffic to and from Calama is fairly consistent. Sometimes, even the vans of tourist agencies might pick you up - it all depends on your luck.
Hitch hiking to Argentina can take a while too as there is much less traffic. It may help to start walking into the desert, towards the airstrip. Make sure you get stamped out of the country in San Pedro de Atacama, because the border, two hours away, has no Chilean checkpoint (only Argentinian).
Once in the town, nearly all points of interest, restaurants, services, are within walking distance, with the exception of a few outlying hotels. Downtown comprises twelve small blocks, between the streets Domingo Atienza and Toconao from west to east, and Licancabur and Caracoles north to south. This last street is the main one, a pedestrian zone. Be aware that, since mid-2010, it's now forbidden to ride a bike in it. If you look gringo enough, chances are the cops will let you slide-but it's advised not to try. They're fond of ticketing cyclists in the evening. If you can't find what you need in the aforementioned twelve blocks, chances are you won't get it anywhere. Bike rentals are ubiquitous, and prices vary little. It can pay to rent one to visit the Pukara de Quitor, Aldea de Tulor, Valle de la Luna, and even Laguna Cejar. All of these are described in the next chapter.
There are three essential places to visit, plus a host of other very interesting spots. In order of popularity, these are:
Geysers del Tatio
Located at 4,200m above sea level, and a 100km away from town, these are some of the highest geysers in the world. It's also the third-largest geyser site on Earth, with over 80 active ones. Most agencies travel there at 4 AM. The spectacle is hard to forget-even if the geysers themselves are smallish, the backdrop, lighting, and sheer variety are astounding. Usually, you get to see them from the first stages of dawn, an hour before the sun rises, until sunlight bathes them completely. The best time to take pictures is at exact sunrise, but other lightings can also create wonderful pictures. All respectable tour agencies include breakfast for their guests. If you book one that doesn't, then you've been scammed. On the way back, it's typical to find wild vicuñas, an endangered andean camelid that's highly protected in Chile. They were rescued from the verge of extinction thirty years ago. Vicuñas in the area are accustomed to human presence, and will tolerate tourists coming to some twenty meters away-any more, and they're likely to flee. Be extremely respectful of the regulations, for many guides and drivers might even react in an aggressive manner if you bother the animals in any way. A common stop is the fording of the Putana river, a spectacle that for some even surpasses the geysers themselves. Many different bird species inhabit it, and it's perfectly possible to get very close to them-giant coots (fulica gigantea) are especially indolent. Winter has the most birds, with over ten different species cohabiting the place at peak migration, but temperatures are harsh. There's also the possibility of seeing a vizcacha or two (lagidium viscacia), a funny mix between a bunny, a squirrel, and a kangaroo. They're very shy, though, and if you don't get there among the first visitors, they'll have usually disappeared. In the background, to the east, lies the Putana volcano-an active mountain that boasts seven small fumes. Lastly, there's usually the choice of visiting one of two locations. The first one is Machuca, an abandoned altiplanic village that lived from the mining of sulpher. Most regular tours stop here. Nowadays, you'll find a few locals there, roasting anticuchos made of llama meat. Teas, soft drinks and empanadas are also available. The meat is of questionable origins, with some wild theories as to its origin floating around. Ask your guide for a laugh. It's fairly safe to consume, though, as sanitation's decent. Just after exiting Machuca, it's common to see llamas grazing on a beautiful pasture. After that pasture lies a micro-sized salt pan, where vicuñas and James' flamingos can be seen (the latter only in summer, though). The other location is Puritama. If you plan on going, please consider the following things:
Valle de la Luna
Entrance fee: $2000 Chilean Peso (the tours won't include it).The office opens at 9:30am (as of Nov 5, 2014). There is nothing stopping a bike from entering before the offices open, but do support this incredible site by buying a entry ticket.
There is a beautiful mirador (viewpoint) off the paved road to Calama that can be reached by car or bike. This is around km 83. You'll see a small hut off the road. Head towards the rocks that were put there to simulate chairs and tables. There is a bit a climbing with the bike from San Pedro. If the road incline is down for a significant duration then you have passed the viewpoint. This viewpoint is quite a bit after from the turnoff to Valle de la Luna. This is a beautiful viewpoint to see both the sunset and the sunrise. Hardly anybody is there for the sunrise. A little bit of walking away from this point is a spiral maze. I walked in and out the spiral to make a wish.
Commonly advertised as 'Moon Valley' in English, this part of the Salt Mountain Range offers stunning clinal and anticlinal formations in a perfectly barren landscape. Almost all tours include watching the sunset there-you shouldn't miss it. The large stone walls resemble those of the Grand Canyon in Arizona, sans river. There are also huge halite (rock salt) strata that produce a knacking sound all day long. This can be unsettling at first, but it's actually harmless. Among its prime attractions are the Grand Crater, the Salt Canyon, the Three Maries and salt mines, the Salt Caves, the Cari Viewpoint (also called 'Piedra del Coyote'. This location is off the road to Calama and not actually in the Valle de Luna ), and Valle de la Muerte (Death Valley). All tours visit a number of these, but it's virtually impossible to know which beforehand. Summer tours tend to be longer, though, and therefore have a greater probability of including more destinations.
It's perfectly possible to ride a bike there, but you should take your time. Although only 8km away from San Pedro, the road is steep and sinuous. When biking, it's advised to travel early (think 7-8 AM) in the morning, for afternoon temperatures can be suffocating year-round. You miss the sunset, but also lessen the possibility of heatstroke and the sightseeings won't be filled with tourists. Also, it's easier to find someone to rescue you if you get in trouble. Most drivers and guides are willing to help stranded cyclists, especially if they're female, or if you travel with one. Just don't expect them to carry a retinue of ten or so tired bikers! You should get a flashlight especially if you want to watch sunset (the road can be dangerous when dark) but also because there's a cave you can visit and it's pitch black in there. Most bike rentals will lend you a headlight if you ask, but make sure the bike also has a tail reflector, and wear a helmet. Ask also an emergency kit for the bikes and a map of the valley. Kilometro 0 has good bikes (Caracoles street). Prices: $3500 for 6 hours, $6000 for the whole day.
If you plan on going, please consider the following:
Feel like visiting the Atacama salt pan, a picturesque village, and some Alp-lookalikes in a single day? Plus eating some local food? Then this is your thing. Usually advertised as 'Altiplanic Lagoons', the tour varies very little, if at all, between agencies. You'll be visiting the village of Toconao, renowned for its church and bell-tower; Laguna Chaxa, a national reservation which three species of flamingos inhabit year-round, located at the heart of the Atacama salt pan; Miscanti and Miñiques lagoons, located above 4,000m, and home to a variety of local fauna; and Socaire, a tiny hamlet that lives from selling lunch to tourists-it usually includes home-grown potatoes, big beans, carrots, and quinoa, plus a few other things. There are two differents tours, one from 7am to 2pm, with breakfast but no lunch (CH$20,000 to 30,000), or another leaving town at 8am, and returning at 5pm, including lunch in Socaire (CH$30,000 on Sept 2014). If you plan on going, please consider the following:
This is one amazing location... in summer! Set in the northern tip of the Atacama salt pan, this location offers a splendid panorama of the Andes, and the possibility to bathe in waters as salty as those of the Dead Sea. The landscape's also remarkable. It usually ends with sunset, along a simple cocktail with pisco sour. The tour sets off at variable times (since Chile follows DST), but always in the afternoon, around 3-4 PM. Besides the Cejar and Piedra lagoons, excursions usually stop by the 'Ojos del Salar' (Eyes of the Salt Pan), two freshwater eyes very close together, and lake Tebenquinche, a water mirror that offers the absolute best sunsets in the whole area-imagine the mountains slowly changing colors, from yellow to pink, and that same image reflected on the lake's perfect surface! You can get there by bike, but bear in mind that it's a long ride: 50km for the round-trip, with the sun burning your scalp without any mercy. There are shorter paths, but the safest is the main road; to get there, just ask where the customs ('aduana') are, and then travel south until you see a sign that reads 'Laguna Cejar'. The road's paved, and drivers are accustomed to see bikers on it. Wear bright clothing (red, blue and yellow work best), just in case. You shouldn't have any trouble locating it, for there are other signs along the way. If you'd like to visit the other lagoons, besides Piedra and Cejar, you can try asking the employee at Cejar's entry. Spanish is required, though. Unfortunately, no maps show the paths between Cejar and the others, but a simple compass can get you there-ride south, following the tracks of the agencies' vehicles. Again, bring a flashlight. If you plan on going, please consider the following:
There are two ways to get here: either by booking a specialty tour, or by taking a different El Tatio Geysers route. They're commonly called 'Hot Springs', but that name couldn't be more of a misnomer. The Puritama (means 'hot water' in Kunza) is actually a warm river, that breaks loose from the stone a few meters away from the actual place. Water temperature usually is around 33ºC. It is amazingly clear and pure, and hosts a budding population of rainbow trout (don't worry, they're tiny and harmless). The "hot springs" are property of Hotel Explora, a five-star brand located in all of Chile's hot spots. The facilities are basic, yet elegant and extremely functional. The entry fee's something to watch out for: 15.000 pesos (25 USD). If you can spare the money, you won't regret it; the landscape's stunning, and the water perfect. Ancient agricultural terraces line the canyon-sides, along with massive stone walls, and even some cacti. The layout of the place is as follows: there are eight artificial pools, cleverly made with volcanic rocks, so that they mesh perfectly with the scenery. Guides and drivers typically recommend the fourth and fifth ones; unless you're there early, forget about them. Go for the seventh. The water's just a little bit colder, but the pool's very large, and has sizable waterfall that doubles as a hydro-massage. If you plan on going, please consider the following:
In spanish, it's called 'Tour Arqueologico'. It usually comprises three destinations: Pukara de Quitor, Aldea de Tulor, and the R.P. Gustavo Le Paige archaeological museum. Pukara de Quitor is an ancient fortress, most likely built in the tenth century. Entry is 2,500 and can be reached easily by bicycle before continuing on through Garganta del Diablo. (The Garganta del Diablo by bike is not to be missed. It is an excellent excursion you can do by yourself. Bring fresh legs and plenty of water and you'll be rewarded by beautiful views.)It's quite close to San Pedro, only 4km away by dirt road and foreign one creek. The view from the summit is breathtaking. Aldea de Tulor is the oldest village in the Atacama basin, approx. 3,000 years old, and kept in pristine condition. It's part of the Los Flamencos national reservation, and has small exhibits on archeology (worthless) and local flora and fauna (worth a visit). Last, but not least, is the museum. It holds a decent collection of original atacameño pieces, along with some acquired by the ancient inhabitants of San Pedro through trade-these are most exotic. The main exhibit is only in spanish, though, but you can hire a guided tour in spanish, english and french. The schedule for these is published in the museum itself-take a look around. Special, private tours are also available in italian, german, and portuguese; you must reserve these at least two days before. The guides are very capable. The museum also sports a small, but well-stocked souvenir store. They carry some of the finest hand-crafted pieces to be had in San Pedro, plus an interesting assortment of specialized books in spanish and english. You can visit these places by cycling, or even on foot. The museum's right by the Plaza de Armas, the main square. Most bike rentals will give you a map of the area; it should clearly point out where the Pukara is. Getting to Tulor, however, is a tad tricky. You must look for signs in the most unlikely places: wall graffiti, stuff hung from trees, and street names. If you plan on going, please consider the following:
Like most deserts, Atacama has its share of dunes and sand-banks. The most popular is located in Valle de la Muerte (Death Valley). All sandboarding tours will take you there. The dune is almost 100m in height; still, the typical track is barely a fraction of that. Some of them offer also to watch sunset in the Moon Valley-but be aware that you won't visit any of its spots, except the Great Dune or the Cari Viewpoint. If you plan on going, please consider the following:
Salar de Tara
It's perhaps San Pedro's best-kept secret. Or not. It really depends on your interests. The road is long, but well-paved, until you reach the entrance to the most remote part of the Los Flamencos national reservation: Monjes de la Pacana (Pacana Monks). The place is well above 4,500m-consider it carefully, as it's not uncommon for people to get altitude-sickness. After that, it's a visit to some peculiar stone formations, obsidian quarries, more stone towers (called 'Catedrales'), and the huge Tara salt lake. Fauna is abundant, and particular to that environment. The landscape is stunning at all times-it's easy to catch glimpses of Bolivia here and there, as well. Traffic is light, as this destination's not really popular. If that matters to you, then taking this tour is the perfect way of saying 'I was off the beaten track of San Pedro de Atacama'. The schedule's a lot more flexible than in other tours, so harass the driver and guide as much as you like. There are a few optional treks along the way, but they're difficult to attempt. You'll be feeling shortness of breath almost at once. If you plan on going, please consider the following:
Valle del Arcoiris
Or Rainbow Valley. It features three different parts, all of them interesting. The "Hierbas Buenas" petroglyph site is the first, featuring over a thousand ancient stone carvings from the ancient "atacameño" people. They're from all time periods, from the first caravaners to the Incas. Most tours just visit sites 1 and 2, but that should be enough to afford a pretty nifty panorama of these ancient people's history. The other four sites are of difficult access. Then you've got the village of Matancilla, which is only habited according to season. If you go there in winter, be assured you'll find it deserted. The inhabitants grow a variety of crops, which are easily distinguished all through autumn. Dead wild donkeys are all too common, on the side of the road, while goats and llamas are harder to spot. Finally, you've got the namesake for the place: the ever-stunning Rainbow Valley, a series of hills that display countless colors, from white to black, from blue to red. Usually, all tours visit two of the four roads available, where the best views are to be had: The "cathedrals" and the great valley. Next to the former, to the left side, are some ever-mysterious buildings, made partially of serpentine, which gives them a light green color. They're well-camouflaged, so you'll have to climb to actually see them. On the way back from these "cathedrals", there's a beautiful hill that displays a wealth of colors; if the guide doesn't offer you to walk down the slope, ask for it! It's certainly worthwhile. You can watch a similar spectacle in Argentina, on the "Cerro de Siete Colores", but you'll miss the petroglyphs. It might be worth it to rather book a tour in San Pedro, especially since most tourists are completely oblivious of the Rainbow Valley's existence, so you'll most likely be alone when you visit. Most of the advice given for other excursions applies here.
The environs of San Pedro de Atacama sport a large variety of mountains to climb, catering to many levels of difficulty. There's a few specialized agencies that offer this kind of service; be sure that they provide all necessaries, not only asking the clerk, but also the driver and guide! An oxygen tank and climbing rods are the least you should expect. The easiest mountains to climb are Cerro Toco (5604m) and Volcán Lascar (5510m)-they're fairly popular, and take no longer than a day to complete. Higher in difficulty are Cerro Pili (6064m), and Sairecabur (5971m). The beautiful Licancabur Volcano, which towers over the town, is a real challenge; although only 5916m high, it takes at least three days to complete, not counting an exacting preparation period. Another choice is the Kimal mountain (4276m); even when its altitude is not that impressive, it's surrounded in myth and legend. According to local folklore, the "princess Kimal" is extremely jealous, and enjoys snatching adventurers away. There's even a supposed season for climbing her, when she's more pleasant; of course, no agency will tell ever you this beforehand. Take the chance at your own risk. Should you attempt any mountain climb, in any case, you ought to be well aware of the potential risks.
There's still much more to be found in the San Pedro area. From the secluded national reservation at Aguas de Quelana, to the ghastly surface of the Salar de Ascotán, to the most advanced radio-telescopes in the world at ALMA, there's enough sights for half a lifetime. If you are a returning visitor, or someone who loves to see what almost no one else has seen, and you get offered a visit to somesuch place, then take it! Albeit being a tourist attraction for thirty years, San Pedro de Atacama is still full of mystery and wonder.
First of all, Atacama desert is one of the best place on Earth to see the sky. Space Star Tours offers a unique experience in watching them. It starts with a explanation of the naked eye sky. What is a constellation, how to learn them, how to read a sky map and recognize the main stars. They explain you why are there different coloured skies etc. On the second part, there is the largest park of telescopes of any public observatory in south America. So it is possible to see Saturn, other galaxies and a lot of other phenomenons out there. The tours ends with a warm drink and an explanation about astronomy. The tours last two hours and a half. The schedule vary during the year (later during the summer, i.e. January and February). On March 2011 there was a Spanish tour at 10pm and a English tour at 12pm. You are in the desert and the nights are pretty cold, take warm clothes with you. If you are still cold, they can provide you with warm jackets. Cost 30US$
Be careful of giving your credit card details over the phone to ¨guarantee¨a reservation.
First of all, always remember that the the altitude of San Pedro de Atacama is 2400m (about 8000 feet) above sea level. Some of the tourist attractions are well above 4000m (12000 feet). This includes tours to Salar De Uyuni - you will be reaching an altitude of 4300m on your first night! (This corresponds to a 1800m increase in 1 day - no mountaineering guidelines would ever say this is safe!) Symptoms of AMS (acute mountain sickness) are very common. Symptoms include headache, dizziness, nausea, loss of appetite and shortness of breath. Treatment such as oxygen is not readily available, and the guides and drivers have no medical expertise in AMS aside from local remedies.
Therefore the tour is NOT suitable for people who have flown straight in from Santiago or a low altitude. Your body needs 3 days or more in San Pedro Atacama to be ready. It is NOT a matter of age or fitness, and chewing coca leaves will not prevent serious illness.
In more rare cases a progression of symptoms to persistent vomiting, difficulty breathing at rest, or a severe intractable headache that does not respond to simple pain relief (paracetamol and ibuprofen) indicates a serious medical emergency. There is no cure, except heading to lower ground. If you can, be prepared with the necessary medications (eg acetazolamide if you have access to it) and know how to use them. Consult with your physician before booking a trip, especially if you have any heart or lung conditions.
The sun in San Pedro can often emit dangerous levels of UV rays! Especially in summer, using sunblock, sunglasses, a wide-brimmed hat, and long sleeves is essential. In winter, the radiation levels are more tolerable, and you can actually sunbathe. In summer, however, don't attempt it at all! Especially if your skin's white. The bare minimum UPF for sunblock lotion is 45, 60 and upwards being much better. Always remember to reapply it after an hour or so.
Other Health Concerns
San Pedro only has a Posta, a small medical facility with an ER and some assorted doctors. There are no pharmacies in the area, only a tiny shop that sells the essentials: sunblock, aspirin, condoms, anti-allergics, etc. (La Botica, located on Le Paige street, close to the police station) If you become seriously ill, or suffer a major lesion, expect to be transferred to Calama, or even Antofagasta, at great expense! While there are no major hazards in the area (such as lethal diseases, poisonous animals, and so on), take twice the care you normally would when hiking, cycling, and doing any other activity outdoors. This applies even more to the geysers, where burn-related injuries aren't that uncommon; the place is virtually disconnected from the world, so be extremely cautious when visiting!
You can rest assured, there's virtually no violent crime in San Pedro. Extra care is advised when arriving at the bus terminal early morning as easy targets are spotted by bag thiefs. The theft of bicycles and cars happens every once in a while, so take the normal precautions in that regard. Despite being poorly lit at night, the town is safe to walk around at all times-use your common sense if you see something suspicious. You might hear locals say that the only danger in town are stray dogs (leading even to the nickname "San Perro de Atacama"; perro means dog in spanish), and this is true. San Pedro boasts a huge population of them; most are friendly and harmless, but a few will attempt to bite passing cyclists. Rape is not unheard of in San Pedro, therefore it's best practice for women to exercise caution especially at parties where alcohol is involved.
Despite rumors to the contrary, exchange rates in town are decent, but watch out for wild price swings in the currency of your interest-the money exchanges in town usually are lagging behind this info, which can play in your favor... or otherwise. The dollar's very appreciated, and you can routinely get better rates there than in banks. Be mindful, though, that one-dollar and damaged bills won't be accepted. The euro rates are terrible, though, while other currencies' can be found somewhere in the middle. Again, they only accept larger euro bills, and only in mint condition. There's four places with ATM's in town: Banco Estado, in front of the museum (only accepts international MasterCards), Banco Bci (Caracoles-Vilama streets intersection, close to the plaza), Atacama Connection (they have two offices; the one with the ATM is on the intersection of Caracoles and Calama streets), and a last one at the western end of Caracoles, which only accepts international Visas. Until a few months ago, the operation of these ATMs was sketchy, due to frequent money shortages; now, with greater variety, this has somewhat improved. A tip: if an ATM refuses to give you money, it could be because its supply of a certain denomination is spent. Try with a different amount. For instance, if you wanted 35.000 pesos, round it down to thirty-thousand, or even twenty-thousand, and withdraw money twice (or a higher amount, which actually makes more sense).
Be aware that the ATM money supply is limited. On busy weekends it is not uncommon for all of the ATMs to be empty by Sunday and they are not refilled until Thursday. It is advisable not to show up in San Pedro without cash of some form.
This is the most common way of traveling to Argentina. There's three bus lines that go there, Geminis, Andesmar, and Pullman Bus. The prices float around 60 USD (30,000 pesos), and all of them leave from San Pedro three times per week. Other choices can be found in Calama, but it might defeat the point a little, since you'll go through San Pedro again, in any case.
Going to Uyuni by bus can be done only from Calama; the fares are cheap, though, sometimes as low as 8.000 pesos (~20 USD). They do go very early in the morning (6am) so you'll need to stay in Calama the night before. Frontera del Norte (operates Monday, Wednesday, Thursday, Friday and Sunday) and Atacama2000 run this service. You can double check times at their offices in the bus terminus in San Pedro as there is no information online. They operate from Calle Antofagasta in Calama. You change bus at the border but it's very straightforward. Layer up as the bus can be cold for the first half of the journey. (September 2015)
[Warning: If you do end up staying in Calama please be careful. I had my kindle stolen from my hand by a guy on a bike when reading in the central Plaza de Mayo. I had my backpack with me so was a very obvious target. Locals told us afterwards this is very common so be extremely careful with belongings. We were urged to get taxi to the bus in the morning as walking was too dangerous. Taxi cost about 3,000.]
You can also go direct to Uyuni from San Pedro by jeep/ minibus transfer for 25,000. This can be arranged by a travel agent. However you will also have to pay an extra "park entrance" fee of about 150 bolivianos (21 USD). Not all travel agents will tell you this when selling the ticket. You will not have to pay this fee if you travel Calama to Uyuni.
The nearest airport is El Loa (CJC), located in Calama. The usual way to fly there is to take a plane from Santiago; there're flights from Antofagasta and Iquique as well, though. Three airlines stop there, and only for national flights: LAN (has the most flights, and the best support, but isn't always the cheapest), Sky Airline (terrible website, better service than LAN), and PAL. To get to the airport, you have two choices: taking a taxi from Calama (about 5,000 pesos), and then a bus to San Pedro (2,500 pesos); or taking the transfer, Licancabur, that charges a fare of 10,000 pesos in regular trips, and 12,000 for "special" trips (late at night).
The border to Argentina is 2 hours east from San Pedro, but there is no Chilean Control there, only Argentinian. So get your exit stamps in San Pedro before travelling east.
You have to take attention booking with tour operators in Chile, since all the tours in Uyuni(Bolivia) have to be guided by Bolivian tour-guides, chilean tour guides are not authorized to conduct tours in the Uyuni salt flat. A handful of agencies offer 3 days/2 nights tours to Uyuni. It does not really matter who you book with, as they mostly join forces (at least in low season) and fill up their Land Cruisers with people from other agencies. The going price (starting at USD 140, March 2011) is some 40% higher here than in Uyuni, even though the itinerary is identical, only reversed. There is the advantage of there usually only being a few Land Cruisers at each site since you see things at different times of day to tours originating in Uyuni, where there can easily be a hundred tourists at each stop. There's also the possibility to return to San Pedro a day later, for a surcharge of USD 20.
Accommodations are quite basic, with frequent lack of (hot) water and electricity. Meals are filling but hardly gourmet and vegetarians may find themselves a little lacking in protein - bring plenty of snacks as supplies en route are extremely limited. If your tour agency does not provide water, ignore them when they tell you it is easy to buy on the journey-in our experience it was not, and you are better off bringing it all from San Pedro (at least 2l per person per day, although at that altitude more would be good).
A sleeping bag and plenty of warm clothing are essentials, it gets very cold at night.
The first night is spent at Laguna Colorada, at 4370m, so it is advisable to spend several nights in San Pedro, to acclimatise before taking the trip. Even then, AMS is a considerable risk-take the usual precautions, and if you have any reason to be particularly worried about altitude consider taking the tour from Bolivia instead, where you will have far more opportunities to acclimatise to high altitude beforehand.
It is essential to get a written itinerary from the agency, specifying all the sights in the order they are to be visited, and also meals and accommodation (whether shared or not). Some costs may not be included: Bolivian immigration, entry fees for national parks and museums. Ask about these at the agency.
Read travellor reviews of different agencies at the tourist information office. Estrella del Sur has had a lot of good travellor feedback with excellent guides (140 USD, March 2011). Keep in mind that most guides/drivers do not speak English. Choose your tour company wisely.