Call of Duty: Black Ops 3 will have the ability to swim where ever maps may have water. You can go under water and use your weapon; you can have a full combat under water in this game.
Your underwater life-span is not unlimited. At a certain point, your character starts to run out of breath; at that point, you can just thrust jump out and go back in if you want. And, to make a dramatic exit out of the water, you can thrust jump out and surprise enemies.
David Vonderhaar stated that this feature became possible because of the power in the PS4, Xbox One, and PC. With that, we’re not too sure if you’ll be able to swim in Black Ops 3 on Xbox 360 and PS3…we’ll let you know when we find out for sure.