The basis of any dive course is to begin with theory. After learning about things in theory, we can move on to practicing them in a safe, confined body of water. Once we have mastered things in confined water we can then finalize and perfect them in open water. Sound familiar? Professional dive courses follow the same principles as every other course that you have done so far. This means that we are going to need a classroom, a body of confined water (e.g. a swimming pool) and an open water site (e.g. the sea!).