Where can I apply for a re-entry permit at Suvarnabhumi Airport?

It’s really easy and only takes a few minutes. It’s between security and the immigration desks.

Take a passport phot and fill out form before you go saves you hassle and money

You use International Departures 2 and the re-entry permit desk is downstairs after security before the Immigration desks

If you are in CM you can get one at Immigration at Central Festival.. assuming you have time before you go.. you have to be there in the morning (before 11am from memory) and it's a really fast process.. never crowded like the main office near the airport.. personally I'd never knowingly roll up at the airport without already having my re-entry permit done and dusted.. there may be a million to one chance of the desk at the airport being closed.. but that's still too much of a risk for me.. not to mention the added stress attached to it!

Get a multi entry easy

After security, don’t go through the electronic passport gate, over to the right, there’s security guys, go see them, you can get your re-entry permit there.

That's a bit last minute

Haven’t been through Swampy for a long time but I do remember seeing a post saying the re-entry desks had moved.

Perhaps I’m mis-remembering but maybe someone who’s travelled through there recently can confirm.

I got this off AI just now.

Just ask an immigration officer before you go through the automated gates and they'll point you in the right direction.