Das Boot

(abbr. "", ) and also called "" ("the Old Man") by his crew: A 30-year-old battle-hardened but good-hearted and sympathetic sea veteran, he complains to Werner that most of his crew members are boys. He is openly anti-Nazi, embittered and cynical, being openly critical about how the war is being handled.

Jürgen Prochnow

(Ensign) Werner, war correspondent: Naive but honest, he has been sent out to sea with the crew to gather photographs of them in action and report on the voyage. Werner is initially mocked for his lack of experience, and soon learns the true horrors of service on a U-boat.

Herbert Grönemeyer

chief engineer ( or LI, Rank: ): A quiet and well-respected man, at age 27, he is the oldest crew member besides the Captain and is tormented by the uncertain fate of his wife, especially after hearing about a British air raid on Cologne. As the second most important crewman, he oversees diving operations and makes sure the systems are running correctly.

Klaus Wennemann

first watch officer (I. WO, Rank: ): A young, by-the-book officer, he is an ardent Nazi and a staunch believer in the . He has a condescending attitude and is the only crewman who makes the effort to maintain his proper uniform and trim appearance, while all the others grow their beards in the traditional U-Bootwaffe fashion. He was raised in some wealth in Mexico by his stepparents, who owned a plantation. His German fiancée died in a British air raid. He spends his days writing his thoughts on military training and leadership for the High Command. When the boat is trapped underwater near Gibraltar, he becomes pessimistic and begins to let go of his adherence to Nazi ideas as he finally stops shaving every day and wearing his proper uniform all the time.

Hubertus Bengsch

second watch officer (II. WO, Rank: ): A vulgar, comedic officer, he is short, red-haired and speaks with a mild Berlin dialect. One of his duties is to decode messages from base, using the Enigma code machine.

Martin Semmelrogge

("Chief Helmsman") Kriechbaum: The navigator and 3rd Watch Officer (III. WO) always slightly skeptical of the Captain and without enthusiasm during the voyage, he shows no anger when a convoy is too far away to be attacked. Kriechbaum has four sons, with another on the way.

Bernd Tauber

("Chief Mechanic") Johann, also called "" ("The Ghost"): He is obsessed with a near-fetish love for U-96s engines. Johann suffers a temporary mental breakdown during an attack by two destroyers. He is able to redeem himself by valiantly working to stop water leaks when the boat is trapped underwater near Gibraltar. Speaks a lower Austrian dialect.

Erwin Leder

(Senior Cadet) Ullmann: A young officer candidate who has a pregnant French fiancée (which is considered treason by the French partisans) and worries about her safety, he is one of the few crew members with whom Werner is able to connect. Werner offers to deliver Ullmann's stack of love letters when Werner is ordered to leave the submarine.

Martin May

(Petty Officer) Hinrich: The radioman, sonar controller and ship's combat medic gauges speed and direction of targets and enemy destroyers. Hinrich is one of the few crewmen whom the Captain is able to relate to.

Heinz Hoenig

("Boatswain") Lamprecht: The severe chief petty officer shows Werner around U-96, and supervises the firing and reloading of the torpedo tubes. He gets upset after hearing on the radio that the football team most of the crew supports (FC Schalke 04) are losing a match, and they will "never make the final now".

Uwe Ochsenknecht

Ario: The burly mechanic who tells everyone that Dufte is marrying an ugly woman, and throws pictures around of Dufte's fiancée in order to laugh at them both also has a disdainful relationship towards the Bibelforscher, as evidenced throughout the miniseries.

Claude-Oliver Rudolph