[vastlife]

If you are planning to teach English working for Gaba, you don't need any TEFL certification.

I applied for an instructor position at Gaba and was accepted (I turned them down though for web developer job). I have no formal education when it comes to English teaching, except 2 years experience teaching one-to-one English classes in Japan, which I assume helped a lot. I believe the situation at other similar companies (Berlitz, Shane, Aeon) is the same.

Nevertheless, in order for them to support your work visa application you do need to have a Bachelor's degree, which of course can be a necessity if you don't manage to find another way of getting a visa.