U-1021 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), one  Flak M42 and two  C/30 anti-aircraft guns.
U-1021 was equipped with five  torpedo tubes (four at the bow and one at the stern), fourteen torpedoes, one  naval gun of caliber SK C/35 (220 rounds), one  anti-aircraft cannon Flak M42, and two  anti-aircraft guns C/30.