The 1st Submarine Flotilla () is a submarine unit of the Swedish Fleet, established in 1901 and based at the Karlskrona Naval Base within the in Karlskrona, Blekinge County. The flotilla shares its location with the 3rd Naval Warfare Flotilla.
The first form of the flotilla was established in 1904 as unit subordinate to the Coastal Fleet, following the creation of the Swedish Navy's submarine force with the arrival of its first submarine, Hajen. In 1918 the unit was formally named the 1st Submarine Division (1. undervattensbÃÂ¥tsdivisionen). By 1934, it had expanded into a three-division unit, now named the Submarine Department (UbÃÂ¥tsavdelningen). In 1951, the unit was assigned its current name, and was part of the Coastal Fleet as the 1st Submarine Flotilla. During the 1970s, the Navy Diving School (Flottans dykarskola) was added to the flotilla, which later formed the Diving Division (Dykdivisionen), which included submarine rescue ships.
On 1 July 1994, the flotilla was organized as the First Submarine Department (Första ubÃÂ¥tsavdelningen, 1. UbA). This was due to all units within the Swedish Armed Forces being cadre-organized and receiving permanent structures. On 1 January 1998, the flotilla was given its current name, the 1st Submarine Flotilla (). According to the Defence Act of 2004, it was decided that the flotilla and its staff would be relocated from HÃÂ¥rsfjärden to Karlskrona. As of 1 January 2005, the flotilla has been based at the Karlskrona Naval Base.
See below the composite of the submarine force at different time points. During the 1930s, the submarine force was included in the Winter Squadron (Vintereskadern), which was the equipped part of the Swedish Navy during winter time. Parts of the submarine force were included in the Gothenburg Squadron and the Karlskrona Department (Karlskronaavdelningen) during World War II.
The coat of arms of the 1st Submarine Division (Första ubÃÂ¥tsavdelningen) 1994âÂÂ1998 and the 1st Submarine Flotilla since 1998. Blazon: "Or, from a wavy base azure a trident issuant sable".
The flag is a double swallow-tailed Swedish flag. It was presented to the then 1st Submarine Division by the Supreme Commander, General Owe Wiktorin at the Artillery Yard in Stockholm on 30 April 1996.