The design of the IXA was developed to give an increased range, a change which resulted in a slightly heavier overall tonnage.

The Type IXB submarines were the most successful class of submarine in the war in terms of the total amount to tonnage sunk, with each U-boat sinking an average of over 100,000 gross register tons (GRT) during its career.

The Type IXB submarines were equipped with a 10.5 cm SK C/32 naval gun with 180 rounds on a Utof mount.

The last piece of armament that the Type IXB submarines were equipped with were the standard 2 cm (0.79 in) anti-aircraft guns.

After being commissioned and deployed, all of the Type IXB submarines built prior to the fall of France were stationed in the German port city of Wilhelmshaven while those who were commissioned following the capture of numerous French ports during the Battle of France were stationed in Lorient.