Hello,
I just did my first border run to Mae Sai (October 11th 2019) and have a 30 day visa on arrival stamp (I am a British passport holder).
Is the following a possibility?
30 day extension at Chiang Mai immigration, another Mae Sai run and another 30 day extension at Chiang Mai immigration.
Sorry if the information isn't completely clear and thank you in advance.
TLDR : Answer Summary
The user inquired about the possibility of extending their visa exempt entry after a border run to Mae Sai. The comments clarified that they have a 30-day visa exempt entry stamp, which allows for one extension of 30 days at an immigration office for a fee. Additionally, the user can perform another border run to regain a new 30-day entry and subsequently extend that entry as well.