For travel from Vientiane to Bangkok, the buses leave the Vientiane Khua Din International Bus Terminal on Khouvieng Road. Buses are comfy aircon buses and travel to and through destinations in Isaan (Northeastern Thailand) including Nong Khai, Udon Thani, Khon Kaen and Korat.
If travelling from Vientiane to Bangkok by bus you will need to change at any of these destinations. The most popular option is Nong Khai for the overnight sleeper train to Bangkok. I otherwise opted for a 6-hour journey with an overnight stopover in Khon Kaen then forwarded to Bangkok the following morning.
Bus Times for Vientiane to Bangkok
Bus times and prices are printed at the Vientiane bus station as below. Note, these may have changed in 2020.
Vientiane to Korat (86,000 kip): 09:00
Vientiane to Udon Thani (20,000 kip): 08:00, 10:30, 11:30, 14:00, 16:00, 18:00
Vientiane to Nong Khai (15,000 kip): 07:30, 09:00, 12:40, 14:30, 15:30, 18:00
Vientiane to Khon Kaen (50,000 kip): 08:15, 14:45
Friendship Bridge Border Crossing
At the Friendship Bridge border, the bus will stop at the Laos immigration. You will need to leave the bus and pass through immigration. The bus will be waiting for you on the opposite side. The bus crosses the Friendship Bridge and stops again at Thai immigration. Fill in the immigration forms (these are handed out at immigration) and you should be given a VISA exempt stamp on arrival in Thailand which lasts 2 weeks for land border crossings (1 month by airports). Back on the bus again and on to your final destination.
Check here for train times from Nong Khai to Bangkok (Northeastern Route).