In some cases, C Cards can be earned in one weekend. Gomez advised that longer courses are better. It is not just crammed down your throat. Plus there is more individual assistance during the longer courses. There are also private courses.
Most dive shops provide certified instructors and course programs.
Once the C Card is achieved, the diver will be familiar with decompression time requirements, diving safety, hand signals, and be familiar with the equipment. All courses require some swimming pool and open-water diving time. The issuance of the certification car is up to the instructor. He must be assured the student is comfortable in all aspects of diving. There are some individuals who cannot qualify for training.