To prepare for the challenging Army Diver Program, candidates must focus on their physical fitness, pool training, and mobility, and be prepared for the rigors and discomfort of being underwater in dark and murky non-pool environments. 

The Army Diver Program is a challenging multi-stage training program that requires candidates to go through rigorous physical and pool training before they can even qualify for Dive School or Combat Diver School. To prepare for the program, candidates must focus on their physical fitness by crushing the Physical Screening Test, which includes a 500-yard swim, push-ups, sit-ups, pull-ups, and a 1.5-mile timed run. Daily pool training is also recommended, with a focus on improving swimming skills and mobility. Candidates should also practice land training exercises, such as flutter kicks and log training. The goal of Phase 1 training is to test water confidence in dark and murky environments, and candidates must be prepared for both the physical and professional challenges of the program. 

Source: https://www.military.com/military-fitness/how-prepare-your-body-all-phases-of-army-dive-training