His or Her Majesty's Ship, abbreviated HMS and H.M.S., is the ship prefix used for ships of the navy in some monarchies. Derived terms such as "HMAS" and equivalents in other languages such as "SMS" are used.
In the British Royal Navy, the prefix was originally always quoted in full; the first recorded use of the abbreviated form, "HMS", occurred in 1789 in respect of HMS Phoenix. From 1707 to c1800 HBMS (for His Britannic Majesty's Ship) was also used.
Submarines in Her Majesty's service also use the prefix "HMS", standing for "Her Majesty's Submarine". The Royal Yacht Britannia, which was a commissioned ship in the Royal Navy, was known as HMY Britannia. Otherwise all ships in the Royal Navy are known as HM Ships, though formerly when a distinction was made between three-masted ship-rigged ships and smaller vessels they would be called HM Frigate X, or HM Sloop Y.
The prefix "HMS" is also used by shore establishments that are commissioned "stone frigates" in the Royal Navy. Examples include HMS Excellent, a training school located on an island in Portsmouth Harbour, and HMS Vulcan, in Caithness in the Highland area of Scotland, which is established to test the design of nuclear power systems for use in submarines.
The sample ship name used by the Royal Navy to signify a hypothetical vessel is HMS Nonsuch. This is a name that has been used by the Royal Navy in the past; on the eve of World War II the name was given[by whom?] to the Royal Canadian Navy. As of 2012[update] HMCS Nonsuch was the "stone frigate" of the Edmonton Division of the Canadian Naval Reserve.
Prefixing the name by "the", as in "the HMS Ark Royal", while common, is considered bad grammar.
British government ships not in the Royal Navy have other designations, such as "RFA" for ships in the Royal Fleet Auxiliary.
Commonwealth realms and former British Empire
Historically, variants on "HMS" have been used by the navies of British colonies. The practice is maintained in several Commonwealth realms (states which recognise Queen Elizabeth II as their monarch).
- Canada: Her Majesty's Canadian Ship (HMCS) / (French: Navire canadien de Sa Majesté) (NCSM) – Royal Canadian Navy
- Australia: Her Majesty's Australian Ship (HMAS) – Royal Australian Navy
- New Zealand: Her Majesty's New Zealand Ship (HMNZS) – Royal New Zealand Navy
- Bahamas: Her Majesty's Bahamian Ship (HMBS) – Royal Bahamas Defence Force
- Barbados: Her Majesty's Barbadian Ship (HMBS) – Barbados Defence Force
- Papua New Guinea: Her Majesty's Papua New Guinean Ship (HMPNGS)
- Jamaica: Her Majesty's Jamaican Ship (HMJS) – Jamaica Defence Force
- Tuvalu: Her Majesty's Tuvalu Surveillance Ship (HMTSS)
- Colonial: Her Majesty's Colonial Ship (HMCS)
- Australia: Commonwealth Naval Ship (CNS)
- British India: Her Majesty's Indian Ship (HMIS)
- Burma: Her Majesty's Burmese Ship (HMBS)
- South Africa: Her Majesty's South African Ship (HMSAS)
- British Ceylon: Her Majesty's Ceylon Ship (HMCyS)
- Queensland (before the federation of Australia): Her Majesty's Queensland Ship (HMQS)
- Victoria (before the federation of Australia): Her Majesty's Victorian Ship (HMVS)
- Dominion of Pakistan, from creation in 1947 until Pakistan became a republic in 1956: Her Majesty's Pakistani Ship (HMPS)
Seiner Majestät Schiff (pronounced [ˈzaɪ̯nɐ majɛsˈtɛːt ʃɪf]; German: "His Majesty's Ship", abbreviated to S.M.S. or SMS) was the ship prefix used by the Prussian Maritime Enterprise (Seehandlung), the Prussian Navy, the Imperial German Navy (Kaiserliche Marine) and the Austro-Hungarian Navy. It was created by translating the British prefix into German.
It was sometimes also abbreviated to S.M. or SM (for Seiner Majestät) when a ship was mentioned by class, such as S.M. Kleiner Kreuzer Emden ("His Majesty's Light Cruiser Emden").
Special forms included
- S.M.Y. (or SMY) = Seiner Majestät Yacht ("His Majesty's Yacht") for king's or emperor's yacht
- I.M.Y. = Ihrer Majestät Yacht ("Her Majesty's Yacht") for the queen's or empress' yacht.
- S.M.F. = Seiner Majestät Feuerschiff ("His Majesty's Lightvessel")
- S.M.H. = Seiner Majestät Hilfsschiff ("His Majesty's Auxiliary Ship")
- S.M.W. = Seiner Majestät Werkstattschiff ("His Majesty's Workshop Ship")
- S.M.U. = Seiner Majestät Unterseeboot ("His Majesty's Submarine", prefixing a number not a name)
International prefixes for ships of the Royal Netherlands Navy is HNLMS (His/Her Netherlands Majesty's Ship). The Netherlands navy itself uses the prefixes Zr.Ms. (Zijner Majesteits, His Majesty's) when a king is on the throne, and Hr.Ms. (Harer Majesteits, Her Majesty's) when there is a queen. This happens automatically at the moment of coronation. 
The Royal Norwegian Navy vessels have since 1946 been given the ship prefix "KNM", short for Kongelig Norske Marine (Royal Norwegian Navy). In English, they are given the prefix "HNoMS", short for "His/Her Norwegian Majesty's Ship" ("HNMS" could be also used for the Royal Netherlands Navy, for which "HNLMS" is used instead). Coast Guard vessels are given the prefix "KV" for KystVakt (Coast Guard) in Norwegian and "NoCGV" for Norwegian Coast Guard Vessel in English.
Prior to World War II & the subsequent ousting of the monarchy & occupation of the Soviet Union postwar, all Royal Romanian Navy vessels were given the prefix NMS (Nava Majestăţii Sale) or “His/her Majesty’s Ship”.
Abroad, Swedish navy ships are sometimes given the prefix HSwMS (for His Swedish Majesty's Ship), to avoid confusion with other uses of the HMS prefix.
- See ship prefix for a list
- Royal Mail Ship (RMS)
- Category:Ships of the Royal Navy
- HM Prison (HMP)
- Her Majesty's Young Offender Institution (HMYOI)
- Her Majesty's Government (HMG)
- Her Majesty's Royal Palace and Fortress of the Tower of London
- United States Ship
- "Frequently Asked Questions of the Sailing Navy Gallery". www.royalnavalmuseum.org. National Museum of the Royal Navy. Retrieved 18 July 2014.
- "The Evolution of Ship Naming in the U.S. Navy". (US) Naval History and Heritage Command. 22 May 2018. Retrieved 17 December 2018.
Some, but apparently not all, other navies also use prefixes with their ships' names. Perhaps the best known of these is 'HMS' (His or Her Majesty's Ship), long used by the Royal Navy. In earlier times this was also seen as 'HBMS,' for 'His Britannic Majesty's Ship.'
- Justin Reay (8 October 2008). "HBMS/HMS - usage in 18thC". The Society For Nautical Research. Retrieved 17 December 2018.
- "Royal Navy". Archived from the original on 6 February 2006.
- "HMCS Nonsuch". Archived from the original on 30 June 2013. Retrieved 4 August 2012.
- The Guardian style guide
- Australian War Memorial Glossary Archived 2007-06-06 at the Wayback Machine
- "Jamaica Defence Force - Bases". Archived from the original on 1 June 2007.
- "Seemotive, Buchstabe H Letter H".
- The gunboat CNS (formerly HMCS) Protector; 1909 (National Library of Australia)[dead link]
- "Foundation Day oration".
- Port-side view of the former South Australian Colonial gunboat HMAS (ex HMS, ex HMCS) Protector; 1918 (National Library of Australia) Archived February 9, 2008, at the Wayback Machine
- Carl Muller (14 October 2000). Spit And Polish. Penguin Books Limited. p. 117. ISBN 978-81-8475-109-3.
- HMQS Gayundah (Aboriginal for 'lightning') and her sister ship HMQS Paluma ('thunder') (National Library of Australia) Archived February 13, 2008, at the Wayback Machine
- "Department of the Environment and Water Resources: HMVS Cerberus". Archived from the original on 10 February 2007.
- "Welcome (Royal Australian Naval Reserves)". Archived from the original on 13 October 2006.
- IBP USA (20 March 2009). Pakistan Intelligence, Security Activities and Operations Handbook. Lulu.com. p. 151. ISBN 978-1-4387-3721-8.
- "List of Acronyms Preceding the Name of a Ship". Corporation of Lower St. Lawrence Pilots. Archived from the original on 6 July 2011. Retrieved 31 July 2013.
- "Defensieschepen worden meteen Zr. Ms. in plaats van Hr. Ms" (in Dutch). Volkskrant. 29 January 2013.
- Ordbok: "H" Archived 2011-08-12 at the Wayback Machine Försvarsmakten (in Swedish)