Coastal Command was an organization within the Royal Air Force tasked with protecting the United Kingdom from naval threats. More specifically it was founded with the idea of directly countering German U-boats by air. It was formed just prior to WWII in 1936, and was merged into the new RAF Strike Command in 1968.

In the early days of the Command, other arms of the RAF had priority and Coastal Command had to make due with outdated planes and weapons. Supplies of aircraft were so short that many units were in fact "on loan" from the Royal Navy's Fleet Air Arm. Their primary weapon was a small bomb that had to directly hit the submarine. This bomb had a tendency to "skip" off the water, and in one case actually hit and destroyed the plane that dropped it. Early operations were almost comical, often ending with the U-boat the victor in the rare chances they could actually be found by the aircraft.

In 1941 experiments started to see if a depth charge could be modified to be dropped from the air. After a very successful series of tests, the bomb was quickly replaced in service with these new depth charges. In the same year a number of newer planes being introduced into the RAF Bomber Command allowed their older bomber designs to be sent to Coastal Command, including numbers of Vickers Wellingtons. These planes could operate at much longer ranges from shore, making them much more effective. The widespread introduction of sea-search radar enabled these planes to find their targets with greater ease, and soon the U-boats were being attacked throughout the Western Approaches. The introduction of the Leigh Light in 1942 allowed accurate night attacks, denying U-boats the freedom to recharge their batteries under cover of darkness.

About the same time the introduction of the de Havilland Mosquito freed up the Bristol Beaufighter for Coastal Command use. The Beaufighter became one of their most effective short-range aircraft, operating with rockets and depth charges against German U-boats in the Bay of Biscay. These planes were also used in attacks on other German shipping, even attacking the German flak boats originally tasked with shooting other Coastal Command aircraft down near the European shores.

Over the next two years supplies of the very long range Shorts Sunderland and B-24 Liberator allowed Coastal Command aircraft to provide the whole of the North Atlantic ocean with air cover, and losses to U-boats plummeted. It was not so much the number sunk as the constant harassment that made the planes effective, the submarines were unable to run in on the surface at night to attack, meaning that many convoys were able to sail right past the U-boats unmolested.

Coastal Command controlled many formations during WWII. At the start of the war it had four Groups under its control, one of which, No. 17 Group, was a formation dedicated to training aircrews. The other three had responsibility for different geographical sectors of the British coastline. No. 16 Group was responsible for the eastern half of the English Channel and the southern half of the North Sea. No. 18 Group covered the remainder of the North Sea and areas to the north and west of Scotland, north of a line running north west from the Mull of Kintyre. No. 15 Group covered the remainder of the coast of the United Kingdom, principally the south west approaches.

In February 1941, this geographical arrangement was altered with the activation of No. 19 Group. The boundary between No. 18 Group and No. 15 Group was shifted northwards so that it ran along a line heading north west from Cape Wrath and No. 19 Group was made responsible for the southern part of the area formerly under No. 15 Group. In the Irish Sea No. 19 Groups's remit ran south of a line approximately in the middle of Cardigan Bay. In the eastern Atlantic, the boundary ran slightly north of that line.

Further important additions were made to Coastal Command's remit when squadrons based outside the UK were also placed under its control. In November 1940, No. 200 Group at Gibraltar was transferred to the control of Coastal Command, from that of RAF Mediterranean. Apart from a brief period under the operational command of Allied Forces Headquarters during Operation Torch and its aftermath, RAF units in Gibraltar remained under Coastal Command control for the rest of the war. No. 200 Group was raised from Group level to Command level within Coastal Command in December 1941 as RAF Gibraltar, and remained a Command until again reduced to Group level in 1953 as AHQ Gibralter. With the British occupation of Iceland, RAF units were also based there, and as their work was almost exclusively ASW, Coastal Command again assumed control. At first, No. 30 Wing was the formation controlling units in Iceland. However, in July 1941, No. 30 Wing was raised to Command status as RAF Iceland. The final addition to the clutch of overseas units controlled by Coastal Command was No. 247 Group. In mid-1943, Portugal granted Britain basing rights in the Azores, and ASW aircraft were duly sent there. As with Gibralter and Iceland, Coastal Command was the controlling authority for the aircraft based there.

After WWII Coastal Command continued in its anti-submarine role. At first it continued to receive converted bomber designs, notably the Avro Shackleton, originally based on the Lancaster but soon heavily modified. With the introduction of nuclear powered designs the day of the converted bomber were over, and newer planes needed to have considerably more electronics onboard. In 1969 the special-purpose de Haviland Nimrod was introduced into RAF service for this role, and Coastal Command duties were passed onto general squadrons. The command itself ceased to exist on 28 November 1968, when it was subsumed into the new Strike Command. Today there are three active Nimrod squadrons based at RAF Kinloss, part of RAF Strike Command.

Commander in Chief Coastal Command

• Air Marshal Sir Arthur Longmore 14 July 1936 - 1 September 1936
• Air Marshal Sir Philip Joubert de la Ferte 1 September 1936 - 18 August 1937
• Air Marshal Sir Frederick Bowhill 18 August 1937 - 14 June 1941
• Air Chief Marshal Sir Philip Joubert de la Ferte 14 June 1941 - 5 February 1943
• Air Marshal Sir John Slessor 5 February 1943 - 20 January 1944
• Air Chief Marshal Sir William Sholto Douglas 20 January 1944 - 30 June 1945
• Air Marshal Sir Leonard Slatter 30 June 1945 - 1 November 1948
• Air Marshal Sir John Baker 1 November 1948 - 1 January 1950
• Air Marshal Sir Charles Steele 1 January 1950 - 8 June 1951
• Air Marshal Sir Alick Stevens 8 June 1951 - 8 November 1953
• Air Marshal Sir John Boothman 15 November 1953 - 5 April 1956
• Air Marshal Sir Brian Reynolds 5 April 1956 - 1 June 1959
• Air Marshal Sir Edward Clifton 1 June 1959 - 10 August 1962
• Air Marshal Sir Anthony Selway 10 August 1962 - 22 January 1965
• Air Marshal Sir Paul Holder 22 January 1965 - 2 September 1968
• Air Marshal Sir John Lapsley 2 September 1968 - 28 November 1968