Thousands of people arrive in Thailand every year to do volunteer work at a school, charity or foundation. While it might seem it should be an easy thing to do – work for free to help places less fortunate than yourself – the Thai government doesn’t make it simple.
Doing any kind of volunteer work in Thailand, requires you to submit specific documentation to be issued the appropriate travel visa to be allowed into the country.
To be legally allowed to enter Thailand with the purpose of doing volunteer work, you must have the appropriate travel visa stamped in your passport. The visa is called a Non-Immigrant O Visa, and you can apply for it at any Thai consulate or embassy before you arrive in Thailand.
To get a volunteer visa you will need a letter from the organisation you will be volunteering with, confirming they have offered you a volunteer position, and that they are requesting approval of a temporary stay for you. You will need to contact the organisation direct in order to arrange this and see what their policy is on this visa. You will also need to supply proof of funds to show you can support yourself during the time you volunteer.
Most organisations are happy to arrange this for you if you are volunteering long term. If you only plan to visit for a week or two, then they will not grant you this due to the amount of paperwork involved.
Wither its right or wrong, the majority of people come in on a tourist visa and volunteer on this. This is entirely your own choice and you do so entirely at your own risk. Be aware this is illegal but what you do is up to you.