What are the entry requirements for returning to Thailand after traveling to Cambodia on a non-o visa?

Cambodia just visa on arrival only show vaccine chart pay 30 dollars and you in. Can also extend your visa easy country

Can’t answer the Cambodia bit, but to make sure you have hassle free entry (no guarantee as it’s up to immigration) you need the three “proofs”.

1. 20,000 baht cash or equivalent in a major currency. It needs to be in cash. A bank statement, credit card or phone app showing you have funds won’t suffice.

2. Accommodation booked for at least the first few days. If you’re staying with family or friends then have them write an invitation letter for you to stay at their place.

3. A flight out booked within the number of days your entry allows, regardless that you can get an in country extension. 30 for Exempt, 60 for Tourist Visa (although the likelihood on being asked if you have a actual tourist visa is minimal).