Direct non-stop hour and a half flights from Jorge Newbury Airport (Aeroparque) in Buenos Aires. This service is run by Aerolineas Argentinas. Tickets cost around 1000 AR$ each way, but can be cheaper if you book in advance. From the airport, you can take bus 28 into the town centre. It takes around 40mins and costs 3,25 AR$. Taxis from the airport cost 75 AR$ to the centre of town.
You can take a comfortable overnight sleeper bus from Retiro bus station in downtown Buenos Aires. The trip lasts approximately 12 hours. A number of companies run this route, including Via Bariloche, Crucero del Norte, Expreso Singer (a company based in Misiones), Rapido Argentino, Rio Uruguay. A semi-cama service costs around 500 AR$, a Cama/Ejecutivo service around 600 AR$. From the bus terminal, you can take a number of bus services into the centre of town including bus 21 and 14, or catch a taxi which will be around 45 AR$.
Fivefold cheaper than the bus, "The Grand Captain" train operates two times per week from Buenos Aires Federico Lacroze railway station to Posadas. 98/155 AR$ one way tourist/premier class. For more information visit: http://www.sateliteferroviario.com.ar/horarios/posadas.htm. However, due to a dispute between the train operator and the State, "this service was suspended from the start of 2012." It has been replaced by a different service, using much smaller trains, at a vastly increased price (270 AR$ per person as on 13 February 2012). There is also a reduced service, with only one weekly departure (Sunday). Apparently the trains were designed for regional services, not long-distance travel, so this is a stop-gap solution and the situation may develop in the future.
Travellers from Uruguay can, for instance, take the bus from Salto to Concordia. This trip takes approximately 1 hour and costs 85U$ (06/2012). Immigration is done during this bus trip. From Concordia in Argentina take a bus or night bus to Posadas or Puerto Iguazu. This trip takes about 12 hours and can cost $150 (semi-cama w/o service) - 400 (cama w/ service) Argentine pesos (06/2012). From Posadas, a 5 hour bus trip to Puerto Iguazu costs $90 Argentine pesos (06/2012).
In town you will find plenty of taxis and buses, but the best way to get around is on foot.
Bus journeys cost 3,25 AR$.
Parque República del Paraguay, La Bajada Vieja, Botanic Garden, La Costanera riverwalk, Palacio del Mate, Anfiteatro Manuel Antonio Ramírez, and the local museums.
There is a lovely walk along the river which can even be romantic in the evening. Depending on weather conditions it is possible to see the glittering lights of Encarnación in Paraguay. The Posadas 'Costanera' is always packed with locals enjoying their free time. It has plenty of bars and restaurants lining it.
Don't forget to enjoy a Maté, Argentina's popular beverage. Although the first taste will be an unusual flavor for newcomers, it is a haunting taste that beckons you back time and time again. You will see locals walking around with their "equipo de mate" - a thermos flask, the mate gourd and some extra yerba and sugar. Misioneros (the people of Misiones) drink mate more than any other Argentinians, which is not surprising considering they produce it in tonnes for the rest of the country. You will also see, especially during summer, a cold version of mate, called tereré. It's an import from neighbouring Paraguay and is incredibly refreshing on a hot, humid Posadas day.
There is a cinema, run by Sunstar Cinemas, based in the shopping mall on Bolivar and Colon. Tickets cost 40 AR$. (Less for concessions and more on the weekend.)
There are a number of clubs ('boliches') in Posadas. For a more sophisticated night by the Costanera, head to the very popular Cristobal. Most students can be found in Power, on the corner of Av. Corrientes and Av. Centenario. At any club or bar, expect to hear plenty of cumbia, the Argentine's (arguably) favourite genre of music.
===Same day Paraguay Visa===
(Note that British and South African (and I believe most European) passport holders do not need a visa to enter Paraguay)
The Paraguay Consulate in Posadas, Argentina is in a small, orange, old colonial house a couple of blocks from the town center at 179 San Lorenzo (the street numbers were changed but the locals still prefer the old numbers - the new number is on the 1500 block) between Santa Fe and Sarmiento. There is no sign on the building, just a Paraguayan flag (red, white, and blue broad stripes) hanging in front with the old street address - 179. I entered the air-conditioned consulate on a Monday morning and there were just a few people inside and I didn´t wait more than a minute, not like the chaos at the consulate in Buenos Aires. The requirements for American citizens are to get 3 photocopies for each of the following:
1. Passport Info Page 2. Argentina Entry Stamp(in passport) 3. A credit card(only front side) 4. Round-trip transport (it appears you can´t just buy a bus ticket to Encarnación from Posadas - in the unlikely event they do require proof of onward travel you could book a tour to the Jesuit Ruins just 30k inside Paraguay from one of numerous travel agents in Posadas)
In addition to the above you need to give them 3 passport photos which you can get along with the photocopies at a shop right next door for US$4. A single entry visa cost US$65 and a multiple entry visa costs US$100 in cash only and they provide change. You then fill out a simple one page personal info form. (if you make a mistake and cross anything out like I did you will have to fill out a new form) After about an hour he will ask for your right thumb print on three pages which you will also sign. Even though there was a Yellow fever outbreak in Paraguay there were no requirements or even notification. I got a free yellow fever shot at the hospital two blocks from the bus station in Encarnación, after I crossed the river into Paraguay. The whole process can take around 2 hours.
The frequent(every 10 minutes) and crowded local bus is clearly marked "Argentina - Paraguay" or "Servicio Internacional." It costs 11 AR$ and you can catch it on Entre Rios, just a couple blocks south of the town center.
Beautiful artesanal objects handmade by the Guarani Indians. You can find them at Plaza 9 de Julio in downtown Posadas.
Along the city's riverwalk, populary known as "La Costanera", there are plenty of great restaurants like Doña Chola, La Ruedita, Barlovento, just to name a few. Most of these restaurants have a wonderful view of the Parana river.
The most popular bars in the city are: Bocatto, Español, Bahia, Vittragge, Mentecato, Status and Barlovento.
Hotel Continental, Hotel Posadas, Hotel Libertador, Hotel Julio Cesar, etc. Complejo La Aventura is for those who prefer to be in direct contact with nature.
Encarnación in Paraguay is a frequent, crowded, and cheap (6 ARS/6,000 PGY - US$1.25) local city bus ride away wich you can catch from the town center. From Encarnacion bus terminal you can take a bus the Jesuit Missions of Trinidad and Jésus about 40 minutes away (7,000 PGY), or onwards to Asunción, 5-7 hours (~70,000 PGY).
Esteros del Ibera can be reached by hiring a private 4x4 with driver for ~1,000 ARS one way. A slightly cheaper option is taking a bus to Virasoro (1,5 hours - 34 ARS/person) and get a car from there ~700 ARS.