For those who are not sure of Western university degree systems, a bachelor degree is required. Some universities offer Bachelor of Science (BSc) courses, some offer Bachelor of Arts courses (BA), some offer both. Science degrees are usually science based subjects such as maths, chemistry, biology, physics, etymology, astronomy, etc. , while arts degrees usually cover all kinds of arts, performing arts, media studies (journalism, movies, TV, visual arts), history, and linguistics; a degree that touches a mix of these arts may sometimes be called humanities. It depends on your university.
The main point being illustrated here is that for the purpose of obtaining a visa and a work permit to teach abroad, both BSc and BA degrees are perfectly acceptable, whether or not the universities offer these as two, thee, or four year degrees.
In Thailand, universities will not always insist on a TEFL by any means. They will however often be looking for substantial previous teaching experience to young adults, possibly also a history of preparing mature students for TOEFL and IELTS, a language or linguistics related degree, and /or something like a PGCE or its equivalent.
For more information, search our board for more threads on this and related topics.