“Learning to teach without classroom practice is like learning to drive without ever encountering traffic”
Most TEFL professionals agree: under ideal circumstances, anyone preparing to become an EFL teacher would undergo several hours of observed classroom-based teaching practice with real students. There is simply no substitute for this kind of experience as you learn to teach.
However not everyone can afford to undertake a course with teaching practice included, especially when doing a face-to-face course involves travelling to another country, paying for accommodation, etc. As a result, there has been a growth in online TEFL programs.
These courses can be very similar to face-to-face courses in terms of content, but without the teaching practice, especially as modern web technologies allow individual tutorial via Skype. etc.
As always, our recommendation is to research where you want to teach, and find out if an online course is worthwhile. Teaching EFL is a job, and therefore you are in competition with other applicants. A course with teaching practice included will always trump a 100% online course.