21 stunning photos prove the US Navy and US Marine Corps have the best diving boards and swimming pools

While there may not be a lot of downtime at sea, sailors and Marines make the most of their time off with "swim calls."

During these events, they are given permission to swim near the US vessel while onlookers keep an eye out for sharks.

In honor of World Oceans Day, we've collected 21 photos showing that the US Navy and US Marine Corps have the best diving boards and swimming pools.

Related: U.S. Navy issues alcohol ban in Japan:

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