That would depend on where you want to teach. Although I don't have a CELTA, I know of people in Thailand who are teaching EFL with a CELTA or TEFL but they don't have a BA. A lot of these people are teaching out in the provinces away from Bangkok. According to the law, you must have a BA or BS to teach, but in fact this law is relaxed many places, especially out in the provinces where a lot of teachers are needed. I also know of other people who are teaching in Taiwan without a degree.