Some 80 Japanese Type D ("Koryu") Midget Submarines in a dry dock at Kure, 19 October 1945

A midget submarine is any submarine under 150 tons,[1] typically operated by a crew of one or two but sometimes up to six or nine, with little or no on-board living accommodation. They normally work with mother ships, from which they are launched and recovered and which provide living accommodation for the crew and support staff.

Both military and civilian midget submarines have been built. Military types work with surface ships and other submarines as mother ships. Civilian and non-combatant military types are generally called submersibles and normally work with surface ships. Most early submarines would now be considered midget submarines, such as the United States Navy's USS Holland (SS-1) and the British Royal Navy's HMS Holland 1 (both named for the same designer).

Military submarines


Crew of a British X-class midget submarine, part of the British Pacific Submarine Fleet

Midget submarines are best known for harbor penetration, although only two World War II boats, the British X-craft and the unsuccessful Welman submarine, were specifically designed with this in mind. Japan's Ko-hyoteki-class submarines were originally designed to take part in decisive fleet actions. However, as circumstances changed, they were given the task of harbor penetration. Germany's various World War II designs were mostly designed to attack Allied shipping off landing beaches and harbors, although the Seehund had a great enough range to attack shipping off the Thames estuary.

Midget submarines have also seen some use in support roles. X-craft were used for reconnaissance, and the Seehund was used to carry supplies. A number of modern midget submarines have also been built for submarine rescue.


Midget submarines are commonly armed with torpedoes and mines in the form of, for example, detachable side loads and nose sections. Alternatively they may function as swimmer delivery vehicles to deliver frogmen to the vicinity of their targets, which are then attacked with limpet mines.


In civilian use, midget submarines are generally called submersibles; commercial submersibles are used in, for example, underwater maintenance, exploration, archaeology, and scientific research. Other commercially available submersibles are marketed as novelty tourist attractions and as specialised tenders for wealthy yacht owners. Also, a growing number of amateur submariners homebuild submersibles as a hobby.[2][3]

Types by nation





France also acquired a number of German midget submarines at the end of WW2.


German midget submarine Seehund, with a torpedo

Most German midget submarines were developed late in World War II in an attempt to stop the Allied invasion of Europe and used later to disrupt its supply lines. As a result, the submarines mostly engaged in open water attacks rather than harbour penetration.[5][6]


The Indian Navy is planning to acquire two midget submarines at an estimated cost of ₹2000 Crores for use as swimmer delivery vehicles.[12] These submarines will be used for conducting underwater special operations by MARCOS.[13] Both submarines will be constructed by Hindustan Shipyard Limited.[12]


The Indonesian Navy has shown[when?] some interest in having a new Midget-class submarine, built by local shipyards, for coastal rather than open water patrol. The submarine was designed a number of years ago by a retired Indonesian Navy submariner officer, Colonel (Ret) Ir. R. Dradjat Budiyanto, Msc. The midget experiment project involves the construction of a submarine, designated MIDGET IM X −1, which will weigh about 150 – 250 tonnes, with a tubular frame design 24 – 30 meters long, and four torpedo tubes. The submarines will have minimum of 8 – 10 crew members including officers. They will have a 40 km range non-hull-penetrating optronic mast as the attack periscope, and a 20 km range navigation periscope.[citation needed]

Indonesian defence minister Purnomo Yusgiantoro has backed the project. Construction should commence at the Indonesian PT.PAL INDONESIA shipyard by late 2011, and will take about three or four years to complete.



An Italian CB-class submarine in the Nikola Tesla Technical Museum in Zagreb, Croatia


Japanese Type A Midget Submarine recovered in 1960 off Pearl Harbor, Hawaii
DSV Shinkai

North Korea

South Korea








Foca I (SA-41) and Foca II (SA-42) at Cartagena



The Turkish navy has evaluated two midget submarine designs from German firm ThyssenKrupp Marine Systems, Type 200 and Type 300 classes:

United Kingdom

X24 a British X class submarine on display at the Royal Navy Submarine Museum

The Royal Navy has used a number of midget submarines. Most were developed during the Second World War. The decommissioning of the Stickleback class 1958–early 1960s marked the end of midget submarines designed for combat in the Royal Navy.

United States

The US X-1 at sea

Former Yugoslavia

See also


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  6. ^ "German Midget submarine operations - U-boat Operations -".
  7. ^ a b c d e Lenton, H.T. GERMAN WARSHIPS of the Second World War Arco Publishing (1976) pp. 285–286
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  9. ^ Taylor, J.C. German Warships of World War II Doubleday & Company (1967) p.110
  10. ^ Lenton, H.T. GERMAN WARSHIPS of the Second World War Arco Publishing (1976) p.212
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  14. ^ a b Kemp, Paul (1996). Underwater Warriors. Arms & Armour Press. pp. 55–57. ISBN 1-85409-228-6.
  15. ^ a b "By sea & stealth: maritime special forces tend to arrive in hostile territory by sea and by stealth, but where once they would be delivered by rubber dinghies from a submarine now they are using Special Delivery Vehicles (SDV) and even midget submarines". Retrieved December 1, 2005.
  16. ^ Hearst Magazines (May 1942). "Jap Sub Had Guard to Cut Net in Harbor". Popular Mechanics. Hearst Magazines. pp. 71–. ISSN 0032-4558. Retrieved 2 October 2011. ((cite book)): |journal= ignored (help)
  17. ^ "NOAA's Hawaii Undersea Research Laboratory (HURL)". Retrieved 11 November 2014.
  18. ^ a b Watts, Anthony J. Japanese Warships of World War II Doubleday & Company (1967) p.213
  19. ^ Watts, Anthony J. Japanese Warships of World War II Doubleday & Company (1967) p.216
  20. ^ Kemp, Paul (1996). Underwater Warriors. Arms & Armour Press. pp. 225–228. ISBN 1-85409-228-6.
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  30. ^ Preston, Antony (2001). The Royal Navy Submarine Service: A Centennial History. Conway Maritime Press. p. 129. ISBN 0-85177-891-7.
  31. ^ Colville, Tom. "Welfreighter". Archived from the original on 2005-09-22. Retrieved 2008-06-29.
  32. ^ Cole, William (25 July 2009). "Prototype mini-sub shelved". DMZ Hawai'i. Archived from the original on 6 September 2018. Retrieved 5 September 2018 – via Honolulu Star Advertiser.
  33. ^ Kaharl, Victoria A. (1 October 1990). Water Baby: The Story of Alvin. Oxford University Press, USA. ISBN 0-19-506191-8.
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