U-boat campaign

In the campaign version of the game, a player begins their career as a "Lieutenant, Jr." (corresponding to Leutnant zur See), with the choice of initial assignments to a U-boat base between the years 1939 and 1943. The war time and political situation of World War II is reflected in the geographical area and time period which the player begins their career.

The Silent Hunter III campaign will assign the player a certain patrol grid with appropriate naval traffic (such as convoys, destroyer escorts, and task forces) automatically generated by the simulation engine. How the mission proceeds and what targets are attacked is left totally up to the player. The player also has the option to change realism settings on the submarine, adding challenges such as fuel being limited as well as various game play assistance features involving navigation, weapons, and the ability to switch to external camera mode to view the submarine's surroundings.

The most difficult realism setting in the game allows a player to manually target torpedoes for an attack on enemy vessels. In the manual targeting feature, the player must observe vessels, determine their class and nationality, as well as calculate speed, angle on the bow, and gyro angle for torpedo launch. The player also has the option to set torpedo depth and spread shot with multiple weapons. De-selecting manual targeting allows a "Weapons Officer" to make these determinations for the player, although approaching targets at certain angles and determining relative motion is still a factor.

The simulation engine further generates various coastal and port cities, which appear as large harbors surrounded on the outskirts by town buildings, churches, and factories. It is possible for the player to sail into such ports (friendly, neutral, or hostile) and either dock or engage moored targets. Some of the cities available are Portsmouth, Scapa Flow, New York City, Norfolk, Virginia, and Tampa, Florida. Although possible to sail to South America and into the Pacific, the simulation will not generate traffic or port cities for these regions.

The game features a fully 3D U-boat control room, allowing the player the ability to look around the interior of certain submarine rooms. Unlike other submarine simulations, where the crew is often heard but not seen, Silent Hunter III allows the player to see and interact with crew members. The game also tracks the stats of individual crew members, such as rank, experience, morale, and decorations between missions.