A free program for Android, by Brain Vault.

A submarine is a seafaring vessel that can operate independently while being completely submerged in water. It is not the same as a submersible, which has less underwater capability. They can and do a wide range of missions, such as anti-surface and anti-submarine warfare, intelligence operations, mine reconnaissance, land attacks, polar operations, Special Forces support, and defending other fleet ships.

This app is a high-quality 3D submarine simulation with realistic and simple controls designed for your Android tablet or phone. In this game, you can explore a vast underwater landscape, locate a sunken ship, explore passageways, cruise through surface islands, and many other things.