The Peterhead Unit Navy League Sea Cadet Corps No 269 opened in Jan/Feb 1938 under the command of Lt Alexander Birnie RNR who was a communications officer in Aberdeen at the wireless college. Lt Birnie was later to become the 1^st Commanding Officer of Aberdeen SCC Unit T.S. Scylla.

At this time the unit met in the YMCA buildings on a Monday evening. The first uniforms were issued to the cadets in early 1939 and were paid for by the CO. It was also in 1939 when the unit obtained its first boat, an old fishing drifter’s lifeboat and permission was given to conduct pulling in the harbours of Peterhead. In 1940 the unit got its second boat, a lifeboat from the merchant ship ‘Sophie Bakke which had been lost off Peterhead due to enemy action.

The unit's name is not derived from HMS Caledonia as many would believe but from the Caledonian Fish-selling Co. owing to the fact that the then chairman in 1946 was a Provost R. Forman, managing director of the Company.

From the YMCA buildings occupied in 1938 the unit moved to various locations over the years. The YMCA became a services canteen so the unit moved to the Junior Instruction Centre which later became an army barracks. From here the unit moved to the Episcopal Church Hall and thence to the Central School Hall and the Herring sales Room. From the latter place, the unit then moved to the Admiralty yard at Keith Inch before eventually settling down at the custom built premises at the Seagate in 1967. Since 1967 the unit has had several major additions to the building the latest being 2 new classrooms built in 1997/98 and commissioned by the them Lord Lieutenant of Aberdeenshire, Captain Colin Farquharson on 27^th March 1998.