I will be going to school in Bangkok for over a year and am planning on getting my ED visa before I arrive. Would I need a multi or single entry visa? I will be attending school for one year and then another for a few months - both are MOE approved. Do I need to leave the country to get the second ED visa or can my original visa be extended while in Thailand? Thanks.

A multi entry visa requires you leave the country every 90 days or less so most people on education extend inside Thailand - if this is full time study you should be able to extend a single entry for one year and then only have to report address every 90 days to immigration. But if you like to travel and can actually obtain a multi entry visa it might suit your plans better.

Once you get you first ED Visa you can then extend it yearly from within Thailand