Online courses are a good option particularly if you have a limited budget to further your studies or if you have other work and/or family commitments that restrict the amount of time you have available to study. You can find good online courses that provide quality training and allow you to work at your own pace. Having no deadlines but those which you set for yourself is a great advantage. Working on a course with a flexible schedule where your personal tutor can be contacted 24/7 or your coursework can be submitted whenever ready has allowed many of our students – teachers to complete successfully their TESL/TEFL Certificate course, further their knowledge and gain better prospects of employment.
In most places the basic requirements for entry level teaching positions are a degree plus a TESL/TEFL certificate. Being certified will make you more marketable and it will also prepare you for the job.
PM if you'd like to learn more about TESL/TEFL certification with ICAL.