Istanbul to New Delhi over land
Today it is a bigger challenge than it was before these political events and depending on the local political situation it may be possible or not. Borders between countries (India-Pakistan) are closed from time to time. Some places are no longer accessible for ordinary travelers without great risks for their safety.
The route is also part of the Silk Road used throughout ancient times from Europe to Asia.
This route involves crossing three countries from one extremity to the other, namely Turkey, Iran and Pakistan, and some parts of India. Going through Afghanistan may be possible or not depending on the changing political situation there and your evaluation of your personal safety and comfort.
Only information specific to this itinerary is available here. For details on places to visit along the way, see the specific pages.
Avoid going during Ramadan, unless you are prepared to fast.
Police and officials in Eastern Turkey, Iran and Pakistan are quite touchy. Keep a low profile while dealing with them.
Avoid reaching a place in the middle of the night.
An alternate route to India is through Russia and/or Central Asia, described in Europe to South Asia over land. The easiest way to link up with that route from Istanbul might be to get a boat to a Black Sea port.
Western Turkey is visited by tourists from all over the world, so you will find all usual facilities here. But the further east you go, the fewer travelers you will meet, especially if you go away from the main transport facilities. So people there won't be so accustomed to tourists. However, this should not prevent you from visiting those places. See Turkey for all details.
Iran is not much visited by tourists, and that is one of the main reasons to go there. People are eager to meet foreigners and if you get used to the local way of life you will enjoy your trip.
Due to the civil war and the Taliban regime, almost nobody goes there unless they have a good reason to visit. However, since the end of the Taliban regime, NGO members and journalists can get a visa. See Afghanistan for details.
There have always been tourists in Pakistan, although many fewer at times when the country is making news. The land borders have been closed at times during the Afghan war and when diplomatic relations with India were suspended. See Pakistan for details.
India is a favourite with travelers, so in most cities you will get all the facilities you expect as a tourist. See India for details.
Iran, Pakistan and India require a visa for most travelers, so you have to get that beforehand. The embassy of Iran in Ankara and the consulate in Istanbul now refuse to deliver visas if you are not a resident in the country. The situation is the same for Pakistani and Indian embassies and consulates almost everywhere, although there are a few exceptions.
Getting Iranian visas can be a frustrating process for applicants from western countries. As of 2006, the situation for residents of most western countries was that visa applications were often (though not necessarily always) turned down unless the embassy had received a "visa reference number" through the Iranian Foreign Ministry in Tehran. You may be denied a visa if your embassy does not tell you about a reference number requirement, and also because the visa form does not even have a space for the reference number! Reference numbers can be obtained through contacts in Iran (who have to apply to the Foreign Ministry) or through some travel agencies. Some of them, like IranianVisa.com, accept payment over the Internet (roughly €/USD 30 for a normal reference number) and make sure that reference numbers are sent to your embassy within approximately 14 days of application. The costs of obtaining a reference number are in addition to the embassy's visa fees.
Plan from 15 days to several months for a trip, depending on the time you spend at each place. Theoretically, jumping from one bus to another, it can be done in 11 or 12 days, but it would mean never stopping on the way! The length of the whole journey is 7000 to 8000 kilometers.
The actual timing is something like this:
Take your time. Avoid rushing from one place to the other.
In the '90s it used to cost much less than the air trip, even including all hotels and food on the way! It mainly depends on the currency rates of Turkey, Iran and Pakistan. In 1992 the whole trip could be done in 5 weeks for about 350 US dollars.
As of Nov. 2004, total visa costs alone are over $400. In what probably is off-peak travel time (winter and early spring) round-trip flights from New York to Istanbul are under $400. It seems like the most cost-effective way to get to the US is to take a one-way flight (around that same time frame) from Delhi to Tehran on Mahan Airlines for under $400 and then catch a bus/train back to Istanbul.
As of October 2008, a single flight Istanbul-Delhi/Mumbai (or vice-versa) is about 200 Euros with Air Arabia, a low-cost airline based in the UAE. Therefore, going by land is now more expensive than the air trip, however a few hours in a plane have nothing to compare with a few weeks/months traveling through and visiting these 3 countries!
The route can be done in almost all seasons, except winter due to heavy snow especially in Turkey and in adjacent regions of Iran, and the roads are sometimes not passable. A big part of the route in Turkey, Iran and Pakistan is at an altitude of over 1000 meters, so the temperature there is comfortable even in the midst of summer and is cold but dry in winter. However, the great part of Turkey, especially east of Ankara, is very cold and very snowy in winter and the Indus Valley in Pakistan is very hot in summer (May to July).
The book to read before leaving to go on the road is Danziger's travels: Beyond Forbidden Frontiers. It is the story of a hair-raising 18-month overland trip from London to Beijing in 1984 by Nick Danziger (ISBN 0586087060). Another great read is "The Wrong Way Home: London to Sydney the Hard Way" by Australian writer Peter Moore (ISBN 0553817000), in which he travels along the "Hippie Trail". He made his trip in the late 90s, covering 25 countries in 8 months, even venturing into war-torn former Yugoslavia and Afghanistan.
By bus: First there are direct buses to Teheran run by Iranian companies. Straight, cheap, no hassle, but where's the fun? And staying two days in a bus is not the most comfortable way of transportation. Then there are Turkish buses going to Erzurum which are probably more comfortable than the Iranian buses.
By train: There are trains (Vangölü Ekspresi/Lake Van Express) three times a week from Istanbul’s main Asian station (Haydarpaşa) to Tatvan, on the west coast of Lake Van, where you can find a ferry across the lake to Van city (on the east shore). From there on you can catch the train for Tabriz. There is also a once-weekly train service from Istanbul (Haydarpaşa) to Teheran (Trans-Asia Express). Trans-Asia is actually two different trains; in Haydarpaşa you board a Turkish train (every Monday as of June 2008) and ride it all along the northwest-southeast axis of Turkish soil until Tatvan, where you take the ferry and cross to Van. At Van station you get into the Iranian train (although you are in fact still in Turkey; you cross the border while you are inside this train) and ride it until Teheran. These trains cross the border on a more southern location than Doğubeyazıt, so you don’t have a chance to see Mount Ararat (but of course, there are many beautiful mountains along the route).
By ferry: There are also boats across the Black Sea to Trabzon. From there, it is a fairly short bus trip to Erzurum.
Erzurum is the hub for visiting eastern Turkey. If you didn't get the direct bus to Teheran, you will have to change means of transport here. There are buses going to Dogubayazit (4 hours).
Dogubeyazit is the last town before the border. It is mainly a garrison town, but it is also the point of departure for the climbing of Mount Ararat and visiting Ishak Pacha palace (İshak Paşa Sarayı). There are taxis going to the border.
The Turkey-Iran border is at an altitude of 2600 meters, at the foot of Mount Ararat where, according to the Bible, Noah ended up with his Ark.
Tabriz is the first major Iranian city you reach on this route.
Going to Kerman, you have choice of buses or a railway line. There are buses twice a day, which take a full day or a night (about 15 hours). Trains are certainly more comfortable, but run only three times a week. There are even direct buses to Zahedan (22 hours).
If you are not in a hurry, going to Isfahan is worth the trouble. It is probably the most beautiful city of Iran. A bit further in the same direction is another interesting city, Shiraz, and near it are the ruins of Persepolis.
Kerman is a station on the railway line to Zahedan and a hub of southern Iran. Buses to Zahedan take seven hours, but there also is a direct sleeper from Teheran as of January 2012.
Zahedan is the last town before the border with Pakistan.  Take a taxi to the border. You have to bring food and water with you for 2 days. There is no shop and no restaurant before Quetta, 700 km across the desert.
About the food-issue:
According to my experience in 2004, in Mirjave (just after the border),there is a chaishop and in the village there are little markets..
If you take the trip by bus (most likely), there are restplaces on the route to Quetta. The bus stops about every 4 hours and at many checkpoints.
The Iran-Pakistan border post, called Mirjave, is in the Kavir-e Loot desert, which is in the middle of nowhere. This is the real border between the East and the West.
The border closes in the early afternoon, and you can't stay there because there is no accommodation available. You will have to go back to Zahedan if you reach the border too late. You might be able to find accomodation in the town of Mirjave, some 10km from the border post.
Once you cross the border, you have to wait for a bus. From here driving is on the left.
Don't change money directly at the border, it's better to do it in a shop at the main square of Taftan. They change Rials and dollars at an acceptable rate.
There are trains from Taftan to Quetta the 3rd and 17th of every month.
Quetta is the first place you reach when entering Pakistan coming from Iran.
From here, there are direct trains to Lahore.
There are buses and taxis going to the border. In January 2004, the Lahore-New Delhi train was restored. It is probably more comfortable than the bus, but slower, as it used to stop at the border for hours while the police checked people and luggage. Also trains are much less frequent.
The Pakistan-India border has been closed and reopened several times during recent years, so check beforehand. In January 2004, the Lahore-New Delhi train was restored.
Alternative route through Afghanistan
From Teheran to Lahore, there are two main routes.
The usual route today is as shown above. Swing Southeast from Teheran to enter Pakistan at its extreme Western edge, bypassing Afghanistan. This is safer. Travelers with any caution at all should avoid Afghanistan.
The main overland route of the 60s and 70s went East to the Iranian city of Mashad, then to Herat, Khandahar, Kabul in Afghanistan and down through the Khyber Pass to Pakistan. This is described below, but is generally considered too dangerous today.
Afghanistan was scary even in the 70s; most of the men carried rifles and they all had knifes. However, nearly all the guns were single-shot, mostly muzzle loaders with quite a few 19th century British army Martini-Henrys with lever action. Then in 1979, the USSR invaded them. Soon many Afghans had AK-47s. Today nearly every Afghan man has an automatic weapon.
Of course, not all Afghans are likely to take potshots at tourists, or to kidnap one. Most are friendly, helpful, and hospitable. However, as the only country to be invaded by both the USSR and the US, they do have some reason to resent light-skinned foreigners. With everything still (as of mid-2007) chaotic, going there is spectacularly risky, though details of the dangers change from time to time.
If you do decide to risk Afghanistan, see our article on War zone safety.
Mashad is the largest city of Eastern Iran and the capital of its province.
There are daily trains to and from Teheran. Buses take 14 hours to Teheran. Buses to Taybad take about four hours.
There are minibuses and taxis to the border, called Eslam Ghale, 11 km away.
From the Afghan side, there are buses to Herat.
Herat is a big, rich Afghan city, influenced by Iranian culture. It is well-developed because of trade with Iran and in a good shape compared to other Afghan cities. The people are very friendly and hospitable to foreigners and are also more religious than people in Kabul.
No tourism exists in Herat, but there is a small community of foreign workers from Europe or other Western countries. They are easy to find by asking in the German or Indian consulate or hanging around in the Marco Polo Hotel.
Most Afghan roads are very poor. You need a four wheel drive vehicle with a winch to even consider driving on them.
One exception is the main highway from Herat in the West to Kabul in the East. This swings widely South via Kandahar; the centre of the country is filled with impassable mountains.
There is also a good highway from Kabul North through the Hindu Kush to Mazar-e Sharif and the border of Tajikistan in Central Asia. This road contains the Salang tunnel, which is the longest in the world. It was built with Russian aid and then used for the Russian invasion.
Kandahar is the main city of Southern Afghanistan.
It was a major stronghold of Taliban, and among the last places to surrender in the recent war.
You can go South from here to Quetta, Pakistan.
The way from Kabul to Peshawar takes about ten hours.
From Kabul to the border
Buses start early and need about eight hours to reach the border. The road is not in a very good shape so don't expect a very comfortable ride. The price is between 200 and 250 Af (below 4 Euro) if you pick up a mini van bus with ten to twenty other people together. Tall people will be more comfortable in the front seats. These vans are sometimes a little more expensive.
Taxis are faster and more expensive.
Jalalabad is a moderate-sized city between Kabul and the border. If the political and security situation permits (not likely, as of mid-2007!), consider spending a night there. Starting from Jalabad in the morning lets you avoid the crowd by getting to the border ahead of people coming from Kabul.
The border closes at lunchtime.
From the border to Peshawar
Buses and taxis end at the border. People need to cross the border on foot and take a second bus or taxi. Foreigners (non-Pakistani or non-Afghani) have to get a permission to cross the tribal areas, which are located between the border and Peshawar and are controlled by tribes and not by the Pakistan government. The permission is free but a soldier will take you with him in a taxi. The soldier will cost about 100 Pakistani (1.4 Euro) and the taxi twice that.
The way goes through the legendary Khyber Pass.
The travel seems to be secure for travelers who know what they are doing. The traffic is the biggest danger thus it could be recommended to travel on a Friday when the traffic is lighter than the other days. If possible take a good driver you know already. Buses may drive safer than taxis because they are slower.
Peshawar is a huge city in Pakistan. The city has a lot of traffic and seems to have a good economic situation.
Places to stay
There are many hotels and guest houses with western standards. Especially in the "University Town" district and in the city centre.
Places to visit
Other places to visit along the way
Some other places are worth a visit, but you don't necessarily have to pass through them on this journey.