I entered Thailand on my UK passport and on the 30-day visa exemption, which would have expired tomorrow. However, today I crossed the Laos border with my UK passport and am now in Vientiane. My original idea was to spend tomorrow and the next day getting a 60-day Thai visa at the Thai embassy in Vientiane, as from what I understood, if I came straight back without a visa on my UK passport I would just get a 7-day extension. But it occurred to me I have my US passport (I have dual citizenship) which I could use to go back into Thailand on a new 30-day visa exemption. Are there any downsides to this? Will Thai immigration cross-reference the two and be annoyed that I have come straight back on another passport? Thank you so much for any help in advance.

You must come back on your UK-passport (as that one has your Laos entry/exit stamp in it) and will receive 30 days on entry on that without any problems.

You were misinformed.

You can get a 30 day entry with your UK passport. The UK and US both get 30 day entries since they are G7 countries.

Even without the new rules you would of gotten 15 days not 7 days.

You would not be able to enter on your US passport because you would not have entry and departure stamps for Laos in it.

So I could have just come out of the Laos border on my UK passport, turned around, and head back in again to Thailand on my UK passport? And I can do this indefinitely to get 30 days every time?

A post giving illegal advise and the reply to it have been deleted.

So I could have just come out of the Laos border on my UK passport, turned around, and head back in again to Thailand on my UK passport? And I can do this indefinitely to get 30 days every time?

Yes, but after a while they might start asking a few questions.

So I could have just come out of the Laos border on my UK passport, turned around, and head back in again to Thailand on my UK passport? And I can do this indefinitely to get 30 days every time?

Yes, but after a while they might start asking a few questions.

Thank you ! By the way, I noticed that you can get your passport stamped on exit before you actually go into Laos. Do you actually have to go through the Laos border (and by doing so have to buy a Laos visa) before you can go back in to Thailand again?

So I could have just come out of the Laos border on my UK passport, turned around, and head back in again to Thailand on my UK passport? And I can do this indefinitely to get 30 days every time?

Yes, but after a while they might start asking a few questions.

Thank you ! By the way, I noticed that you can get your passport stamped on exit before you actually go into Laos. Do you actually have to go through the Laos border (and by doing so have to buy a Laos visa) before you can go back in to Thailand again?

Unless a passport has both entry/exit stamps from Laos no entry to Thailand will be permitted.

So I could have just come out of the Laos border on my UK passport, turned around, and head back in again to Thailand on my UK passport? And I can do this indefinitely to get 30 days every time?

Yes, but after a while they might start asking a few questions.

Thank you ! By the way, I noticed that you can get your passport stamped on exit before you actually go into Laos. Do you actually have to go through the Laos border (and by doing so have to buy a Laos visa) before you can go back in to Thailand again?

No, you need the Laos entry/exit stamps. You can't just turn around without entering another country.