U-259 was fitted with five  torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one  SK C/35 naval gun, 220 rounds, and two twin  C/30 anti-aircraft guns. The boat had a complement of between forty-four and sixty.
The U-259 was outfitted with five torpedo launchers (four at the front and one at the back), fourteen torpedoes, one naval gun SK C/35, 220 rounds, and two twin anti-aircraft guns C/30. The submarine had a crew of between forty-four and sixty.