HMS H44 was an H-class submarine of the Royal Navy. She was built by Armstrong Whitworth and launched on 17 February 1919. She served in the Second World War. She had a complement of twenty-two crew members. She was sold in 1944 and was broken up at Troon in February 1945.
Like all post-H20 British H-class submarines, H44 had a displacement of at the surface and while submerged. It had a total length of , a beam of , and a draught of . It contained a diesel engines providing a total power of and two electric motors each providing power. The use of its electric motors made the submarine travel at . It would normally carry of fuel and had a maximum capacity of .
The submarine had a maximum surface speed of and a submerged speed of . Post-H20 British H-class submarines had ranges of at speeds of when surfaced. H44 was fitted with an anti-aircraft gun and four torpedo tubes. Its torpedo tubes were fitted to the bow and the submarine was loaded with eight torpedoes. It is a Holland 602 type submarine but was designed to meet Royal Navy specifications. Its complement was twenty-two crew members.