Visa on arrival is available for most nationalities and lasts 30 days. Sometimes there is no-one at the airport who can issue the visa so you have to leave your passport and come back the next day to get your visa.
Entry by Land:
There aren’t many Tajikistan embassies around the world and in the local area the best embassies are the following:
This embassy issues visas in 1 day but needs an LOI, available from local tour companies, or try the online services of Stan Tours who as said before are very efficient
The embassy in Bishkek is hard to find but the process is fairly efficient. We wrote a letter to the Tajik government asking for a visa and explaining why we wanted to go there while sitting in front of the Consular official. They were very friendly and helpful and suggested what to write. We got our visa 24 hours later, handed to us through the gate by a disembodied hand. No LOI was needed.
This embassy isn’t recommended but check on the Thorn Tree for current info
GBAO Permit for the Pamir
If you are entering from Kyrgyzstan to ride the Pamir Highway, you will also need a GBAO permit, available through ITMC in Bishkek or again online through Stan Tours. David from Stan Tours offers good advice even if you aren’t going to use his services.
If you are in Bishkek or Dushanbe you might be able to get the original permit but most companies email or fax you a copy of it and you then show this at the border (if you enter from Kyrgyzstan) and pick up the original of your permit in Khorog, the main town in the GBAO region.
We met many people who had no problem with this method.
Uzbekistan and Kyrgyzstan have embassies in Dushanbe where you can get visas. Check the other country pages for more information about the process.
China: There is no border crossing to China open to foreigners although the government keep saying that they will open the pass between Murgab in Tajikistan and Tashkurgan in Xinjiang province. Some commentators think this will never happen, despite it being a busy trading route for Chinese goods to the Western Pamirs.
Afghanistan: It is possible to cross into Afghanistan but you should check on the Thorn Tree for the latest information.