Tom Clancy's SSN is a simulation of the 688i (i.e. Los Angeles-class) nuclear hunter/killer submarine. You are in command of USS Cheyenne in a limited war against China over the Spratly Islands in a 15-mission campaign where you'll perform a wide variety of missions from patrol to escort, from boomer hunt to convoy attack.

The game uses a lot of video briefings and "news" reports to enhance the atmosphere both before and after the missions. During the mission, you can see your submarine in a 3rd-person view with rotate-able camera (only horizontally though). You are limited to only torpedoes (no Harpoon antiship missiles). While VLS (vertical launch system) is included, it has no real effect in the mission. Sonar is vastly simplified, leaving you only with command decisions like where to turn, what depth to go to, when to shoot, when to use active sonar, when to deploy decoys, and so on. Thermal layers (large difference in water temperature, affects sonar performance) is simulated.