There are  pros and cons to consider when choosing  online TEFL training or in class training. Before taking an online course be very careful and make sure that the course is an accredited tefl certification online, because there are some scams out there. That being said, the first thing  to consider is cost, you can get your TEFL certification online cheap, much cheaper than in a classroom. The con is that you are unable to gain experience or teach English lessons during your training, as you would in a classroom. The hands on experience gain in the classroom  is invaluable and will help you when you are teaching English in a real world setting. If you don't have a lot of flexibility and need to stay in your place of residence then online courses are a good option. Although this does not allow you to become immersed in the culture or help prepare you to be an English teacher in foreign countries as well as teaching English to foreigners as part of your training in the classroom would. Another pro to taking classes in the country you will be teaching in is that you will have the ability to network and work with colleagues in order to find TEFL offers and English teacher jobs. The Pros of learning in a classroom far outweigh the pros of an online course to prepare you for teaching English as a foreign language