East Coast Naval Base^[3] (Swedish: Ostkustens marinbas, MarinB O) was a Swedish Navy command body which operated in various forms between the years 1928 and 2004. It was located in Stockholm from 1928 to 1966 and then in Haninge Municipality from 1966 to 2004.

In accordance with the Defence Act of 1925, from 1928, six regional command and maintenance bodies for the Swedish Navy were organized within the respective coastal areas.^[4] During the 1930s, the regional naval structure was built in the form of naval districts (initially only in the war organization, but later in war as well as in peace).^[5] The East Coast Naval District (Ostkustens marindistrikt, MDO), based in Stockholm, stretched from Öregrundsgrepen, near Gräsö (Björn's Lighthouse) to the northern part of Kalmar Strait (Kråkelund).^[6] The naval districts replaced the naval stations^[7] and were upgraded in 1957 to naval commands (marinkommandon) and was given operational responsibility (higher regional level).^[5] From 1966 to 1990 they were called naval bases (örlogsbaser) and patrol areas (bevakningsområden).^[7] In 1966, new and from then on integrated military districts were established, which took over some of the tasks of the naval commands. Other tasks were transferred simultaneously to the newly established naval bases (lower regional level). During the period 1981-1990, the naval bases were amalgamated with respective coastal artillery defence and formed naval commands - now at a lower regional level.^[5] For East Coast Naval Base (Ostkustens örlogsbas, ÖrlB O), this meant that it was amalgamated with Stockholm Coastal Artillery Defense (Stockholms kustartilleriförsvar, SK) and formed the East Coast Naval Command (Ostkustens marinkommando, MKO).^[8]

The lower regional organization had command duties and was responsible for, among other things, maritime surveillance and maritime maintenance, base services.^[7] The majority of the regional structure was discontinued in 2000 and replaced with two naval bases and a naval shipyard. At the same time the Naval Tactical Command was established.^[7] The organization was formed on 1 July 2000 and took over certain parts of the operation after the East Coast Naval Command (Ostkustens marinkommando, MKO).^[9] The Naval Base was formed on 1 January 2005 after the Defence Act of 2004. The Naval Base took over the main tasks previously relinquished to the East Coast Naval Base (Ostkustens marinbas, MarinB O) and the South Coast Naval Base. Today, it is the Naval Base, which has in principle taken over the remaining naval tasks of the lower regional structure.^[5]

Commanding officers:^[14]