Applying from abroad: You can apply for a non-immigrant “ED” visa at the Royal Thai Consulate in your country country. This visa is valid for 90 days and the application fee depends on the respective Thai Consulate where the application is being filed.
Applying from Thailand: If in Thailand on a non-immigrant “O” visa, a tourist visa or a different type of visa, you can apply for a visa conversion to a non-immigrant “ED” visa at the immigration department in Thailand. The new student visa obtained will be valid for 90 days and the fee for visa conversion is 2,000 THB.
When the application has been successful, the student will receive a non-immigrant “ED” visa, valid for 90 days from the date the student enters the Kingdom.