Here are the requirements for a Teacher's License in Thailand(as explained by Assoc. Prof Dr. Praphon Jearakul and Assist Prof Dr. Poonsap Naknaka of Suan Dusit Rajabhat University):

1. Bachelor of Education Degree or Equivalent*
2. 20 hours training on Thai culture and Teacher Professional Code of Ethics
3. If appointed as a teacher before June 11, 2003(grand-father clause):
   1. Teacher Appointment Letter or Employment Contract(must show the date) - photocopy only
   2. Teacher Permit Certificate from Admin Office of Private Education Commission(Sor Chor 11)-photocopy
   3. Teacher Appointment Certificate from Admin Office of Private Education(Sor Chor 18 or 19)-photocopy
   4. Copy of passport, visa, work permit, educational quals, and 2 passport photos.
4. If appointed after June 11, 2003:
   1. Teaching credential from foreign country(for one without B.Ed. or Equivalent)-photocopy
   2. Recommendation Letter(presumably your school recommends you for the license)-photocopy
   3. Certifications(transcripts, degrees, etc)-photocopy
   4. 500 Baht receipt for registration fee - photocopy
5. Application form, available from Teachers Council of Thailand

*Equivalences to a B.Ed.: The following are considered the same as a B.Ed.:

1. Teacher License from a foreign country(Philippines excluded).
2. Postgraduate Diploma/Certificate: e.g. PGCE, Grad.Dip.Ed., DipTESOL, DELTA.
3. 27 credit-hours of University courses which cover the "Standards of Teacher Knowledge", as discussed below(#3).
4. Passage of the "Teacher Professional Knowledge Tests" . There are 4 tests given twice a year(April and December). Each test costs 1000Baht and takes 4 hours. The tests are given on the weekend(locations unknown) and Saturday is Test I and II, Sunday is Test III and IV. The tests are as follows:
   1. Test I: Language and technology for Teachers/Educational Innovation and IT
      • Study Resources: Heinich, Robert (1993). Instructional Media and the New Technologies of Instruction
   2. Test II: Curriculum Development/Learning Management/Classroom Management
      •  Study Resources:
        1.  Wiles, Jon and Joseph Bondi. (1989). Curriculum Development: A Guide to Practice. 3rd Ed. NY: Macmillan
        2. Burden, Paul R. and David M. Byrd. (1999). Methods for Effective Teaching. 3rd Ed. Boston: Allyn and Bacon(no longer available, check your library). Also see the 5th Edition
   2. Organizational Behaviour in Education. 7th Ed. Boston: Allyn and Bacon

For more information, see Teacher's Council of Thailand.