Thailand’s embassy in Stockholm no longer accepts visa applications by mail.
So there are now only two ways to apply for a Thai visa in Sweden:
Personally or through agents at the embassy in Stockholm.
Or by mail addressed to the Thai consulate in Gothenburg. Info: www.thaiconsulate.se / visa.htm.
The reason why the Embassy no longer accepts applications by letter should be that too many applications arrive with incomplete information.
Swedish citizens only need visas if they stay more than 30 days in Thailand. Expect two to three weeks’ treatment during the peak season of October to January.