Can I enter Thailand with a 30-day exemption, extend my stay, go to Vietnam, and then return?

Yes you can,just do it. You won't regret it.

Yes no problem....we did 60days evisa, going to Cambodia for a month then back to Thailand on a free entry visa then extend for 30 days....staying over all 5 months!!

Just remember you can only do 2 visits into Thailand per your Callander year .

Easiest way for you is do this - I'm going in February next year for 8 weeks so 56 days, So I will get a 60 day tourist visa from Australia and then can extend if I want to stay a few weeks longer, Done

Yes we did it, and we also did another visa run for 30 days at immigration, we didn't need the full 30 days but we did need 6 days which was then covered.

Simple answer is , yes

60 day touristvisa > go Vietnam and come back for a 30 day exempt ..

Andy Moriarty there's no visa in Thailand. There is a visa exempt 30 days without a visa

Should be no problem, providing you have not been in and out of Thailand a lot, during the last year or so

Have you looked at METV?

There is no 30 day visa. I assume you are a passport holder from a western country. You are allowed to enter Thailand without a visa and you will get stamped in to the country for 30 days. Yes you can extend your stay with 30 days.

You can also apply for a 60 day tourist visa before you fly to Thailand and get a 30 day extension, allowing you to stay 90 days in the kingdom.

There's no 30day visa, the single entry visa is 60 days. But you can enter with no visa for 30 days. You can extend that by 30 days