The duration of stay for tourists in Thailand depends on the type of visa and the traveler's nationality. The general details are as follows:

1. Visa Exemption – No Visa Required
Travelers entering Thailand by air can stay for 30 days (with an option to extend for an additional 30 days).
Certain nationalities (e.g., the United States, United Kingdom, France, Japan) may be granted a 45-day stay.
A 30-day extension can be applied for at the Immigration Office.

2. Tourist Visa (TR)
Allows a stay of 60 days.
Can be extended for an additional 30 days at the Immigration Office (totaling 90 days).

3. Special Tourist Visa (STV)
Allows a stay of 90 days.
Can be extended twice, for 90 days each time (maximum stay of 270 days).

4. Visa on Arrival (VOA)
Allows a stay of 15 days (not extendable, except in special cases).

 

Note:
Visa extensions must be applied for at the Immigration Office in Thailand.
Regulations are subject to change; it is recommended to check the latest information with the Thai Embassy or Immigration Office.