While many non-native English speakers have successfully completed Oxford Seminars course and have found placements abroad, most find their first ESL teaching position in their country of origin. With the benefit of this initial experience, many are able to find subsequent employment in other countries.
Your ability to find work outside of your home country will often depend upon the competition for the position that you are pursuing, as well as the visa requirements for that country. School directors usually prefer to hire native English speakers rather than non-native English speakers, regardless of experience.
It is important to keep in mind that in order to qualify for the working visa in many countries, you must be a native English speaker and a citizen of an English-speaking country.