A reminder about the upcoming holiday days for April. Immigration offices around the country will be closed on these days. Airports and land borders are not affected and will operate as normal.
Monday 8th - Substitute holiday for Chakri Day.
Friday 12th up until and including Tuesday 16th - Songkran Holidays.
Be aware that many offices will be extra busy after a holiday day and super busy after a 5 day shut down over Songkran so if you can avoid going in on those days then do so.
Plan accordingly.
TLDR : Answer Summary
In April 2024, immigration offices in Thailand will be closed for the following holidays: April 8th (substitute holiday for Chakri Day) and from April 12th to April 16th for Songkran. Airports and land borders will remain operational. Expect increased crowds at immigration offices following the holidays, and plan visits accordingly. A commenter expressed concern about an appointment overlapping with the holiday closure.