Yes — non-native English speakers can teach ESL, and many Oxford Seminars graduates do. The realistic path: most non-native speakers find their first ESL teaching position in their country of origin, then use that experience to qualify for positions in other countries. The main constraint isn't ability — it's visa rules, since many countries require citizenship in an English-speaking country for an ESL work visa.
Many non-native English speakers have successfully completed the Oxford Seminars course and found placements. Most begin with a first teaching position in their country of origin — and with the benefit of that initial classroom experience, many go on to find subsequent employment in other countries. Your ability to find work outside your home country depends on the competition for the specific position and the visa requirements of the country you're targeting.
To qualify for an ESL working visa, many countries require that you be a native English speaker and a citizen of an English-speaking country. Common visa standards ask that you were born in an English-speaking country, hold citizenship in one, or completed 10–12 years of formal education in a country where English is the primary language. School directors also often prefer native speakers when competition is high, regardless of experience — which is why the first-job-at-home path is the reliable one.
Yes. Many non-native English speakers have successfully completed the Oxford Seminars course. Certification requires strong English proficiency, and the certificate itself is evidence of that proficiency for employers.
In your country of origin. That is where most non-native-speaking graduates find their first position, and a year of real classroom experience meaningfully improves your candidacy for international positions afterward.
Each country sets its own working-visa requirements. Generally, visas require being a native speaker, being born or holding citizenship in an English-speaking country, or having 10–12 years of formal education in a country where English is the primary language. Check the specific rules for each country you're considering.