To be an English teacher in Korea you have to be from one of seven approved countries where English is the official language. Those countries are: United States, Canada, United Kingdom, Australia, New Zealand, South Africa and Ireland.
But starting next year things are changing. People from other countries where English is used as an official language will be able to work in primary and secondary public schools. About 50 countries have adopted English as their official language, but not all of those countries qualify. Only countries with trade agreements with Korea will be eligible. Those countries are: India, Singapore, Malaysia, and the Philippines.
The requirements for the new countries will be more strict than those from the 7 approved countries. Non-native applicants must have at least a Bachelor's degree in English studies and have a teaching license from their country.