A teacher is expected to dress appropriately for class. The best
way to describe the dress code in most schools would be smartcasual.
Smarter than street wear, but not so far as formal dress.
Most organizations don't require their teachers to wear a shirt
and tie. But shorts, beachwear,
Tshirts,
sandals, blue jeans
etc... are usually forbidden. Also the teacher is expected to be
clean and well groomed.
Dressing respectably will go along way towards creating a good
first impression and establishing your credentials as a teacher. It might be a good idea to bring an extra
supply of deodorant with you to Korea. As the Koreans don't use it, and sometimes Westerners smell a
bit 'funny' to Koreans anyway.