In the Marine Corps, a marine must be able to swim and survive in the water.
If a marine can’t swim “he or she is ineffective on 75% of the Earth and cannot be a Global Combat Support System and be Fully Operationally Capable” according to Thebalancecareer.
Swimming, water safety, and water survival in hostile water environments are all taught in the Marine Corps. The Marines were certified to administer swim qualifications for their unit after completing the Marine Combat Instructor Water Survival (MCIWS) course at the Aquatic Center.
The challenge begins before the course starts