When a diver descends in the water the hydrostatic pressure, and therefore the ambient pressure, rises.

For every 10 m in salt water the diver descends, the pressure increases by 1 bar.

As a diver descends, the ambient pressure increases.

Diving suits made of compressible materials decrease in volume as the diver descends, and expand again as the diver ascends, causing buoyancy changes.

The volume of gas in a non-rigid container (such as a diver's lungs or buoyancy compensation device), decreases as external pressure increases while the diver descends in the water.