Do I need to show proof of onward travel when entering Thailand with a visa?

I think the O/P has enough information now to decide what they're going to do. :)

Book a flight or bus ticket out

Unfortunately your airline is wrong, and

@Bi**

is correct ;)

IF you try to check in to a flight here without having bought a visa beforehand AND on a one way flight the airline can refuse you boarding because if for some reason you're denied entry to the country they airline lugs you back on their dime.

I have never heard of someone holding a valid visa (any visa) to thailand being questioned by the airline when checking in on a one way ticket because the fact you hold a visa means if you're denied entry YOU pay your own way out of the country.

@Rob***

, is also correct about the 3-proof-ofz that you can be asked to show when stamping into the country. However in reality of the thousands of people who stamp in to thailand every week few if any are asked.

If you travel with a visa then I believe the airline is not responsible for your return travel should you be refused entry. Therefore they will let you board without proof of onward travel.

@Den***

, if you already have confirmation from the airline company it is no problem than just go ahead with your plans.

I myself have been initially denied boarding from London Heathrow to BKK because i did not have a ticket out of Thailand. My return ticket was from Manila as i intended to buy my ticket bkk to Manila when i was in Thailand.. After alot of messing about and arguements i was allowed to sign a disclamer that id pay any and all the airline costs if i was denied entry at BKK. I was lucky enough to blag that. I know of a few that have been denied boarding without return tickets or proof of onward travel

The immigration officer who check your passport and stamp you into Thailand is allowed to ask you three proofs, funds of min 20.000 Thb or equivalent in cash, accommodation and proof of onward flight. For first time tourists there is a very small chance they ask, if you have a longer history of entries in Thailand with Visa Exempt and Tourist Visa the chance is getting bigger. The airline company is official responsible for your return flight if you have no visa, a one way ticket and you got denied entry. Some airliners take this serious, others don't see it as a big problem.