August closures.
Please note that immigration offices around the country will be closed on August 1st and 2nd (Buddhist Lent day and Asalha Puja day) and also on August 14th (a substitute day for the Queens birthday on the 12th).
Plan accordingly.
Land, sea or air borders are open as normal.
Edit: It appears that July 31st is also a holiday too. This means immigration offices will be closed from the 28th July until the 2nd of August and will reopen on the 3rd August. Avoid the 3rd if you possibly can. Many offices will be super busy with that amount of time being closed.
TLDR : Answer Summary
In August 2023, immigration offices in Thailand will be closed for Buddhist Lent Day on August 1st and 2nd, as well as on August 14th, which serves as a substitute holiday for the Queen's birthday. Additionally, offices will be closed from July 28th to August 2nd due to the holidays, reopening on August 3rd, which is expected to be very busy. It's also noted that there will be a 48-hour alcohol ban during these Buddhist holidays.