Physically almost identical to the Ha-1 class, the three vessels assembled in Japan incorporated a number of improvements, including extended bow for improved seaworthiness, improved rudder for surface handling, and an increase in the size of the bridge and conning tower.
Japanese submarine Ha-3 (波号第三潜水艦, Ha-go Dai-san sensuikan), laid down 1 August 1910; launched 5 March 1911; commissioned 12 August 1911 as Submersible No.10; reclassified as 2nd class submersible on 4 August 1916, reclassified as 3rd class submarine on 1 April 1919; renamed Ha-3 on 15 June 1923, decommissioned on 1 December 1929.[2]
Japanese submarine Ha-4 (波号第四潜水艦, Ha-go Dai-yon sensuikan), laid down 1 August 1910; launched 13 March 1911; commissioned 26 August 1911 as Submersible No.11; reclassified as 2nd class submersible on 4 August 1916, reclassified as 3rd class submarine on 1 April 1919; renamed Ha-4 on 15 June 1923; decommissioned on 1 December 1929.[2]
Japanese submarine Ha-5 (波号第五潜水艦, Ha-go Dai-go sensuikan), laid down 1 August 1910; launched 27 March 1911; commissioned 3 August 1911 as Submersible No.12; reclassified as 2nd class submersible on 4 August 1916, reclassified as 3rd class submarine on 1 April 1919; renamed Ha-5 on 15 June 1923; decommissioned on 1 December 1929.[2]
Chesneau, Roger (1985). Conway's All the World's Fighting Ships 1906–1921. Naval Institute Press. ISBN0-87021-907-3.
Howarth, Stephen (1983). The Fighting Ships of the Rising Sun: The Drama of the Imperial Japanese Navy, 1895-1945. Atheneum. ISBN0-689-11402-8.
Jentsura, Hansgeorg (1976). Warships of the Imperial Japanese Navy, 1869-1945. Annapolis, MD: Naval Institute Press. ISBN0-87021-893-X.
Schencking, J. Charles (2005). Making Waves: Politics, Propaganda, And The Emergence Of The Imperial Japanese Navy, 1868-1922. Stanford University Press. ISBN0-8047-4977-9.