What number from my re-entry permit should I include on the immigration form when returning to Thailand?

When returning to Thailand, you should include the re-entry permit number on your immigration arrival card. It is advisable to show the permit to immigration when exiting Bangkok, as it is stamped in your passport. If you are unsure which number to use, you can post a picture for clarification. It is also recommended to check that your permission to stay is correctly stamped before leaving the immigration counter.