The Western Approaches is a rectangular area of the Atlantic ocean lying on the western coast of the United Kingdom. It is roughly the same height as the west coast of Britain, starting directly on the coast and ending in the Atlantic roughly at Iceland. The area is particularly important to the UK, because many of the larger shipping ports lie in this area.

The term is most commonly used when discussing military actions, notably during the First and Second Battle of the Atlantic in which the German Kriegsmarine attempted to blockade the UK with U-boats operating in this area. Since almost all shipping would pass through this area, it was an excellent hunting ground and had to be heavily defended. During WWII the task was so important that it had its own commander, and the HQ was moved to Liverpool to be closer to the action, while most of the fleet HQ was in Plymouth.

The most famous commander of the Western Approaches was Admiral Sir Max Horton, who took command in November 1942 and immediately instituted a series of tactical changes in the way the escort ships were to be used. Organizing them into "support groups" and "hunter-killer groups", they were to operate at longer distances from the convoys and prevent the deadly wolf packs from ever forming. The technique was successful: with more forces becoming available, rapidly improving technology (particularly radar), and information being provided by Ultra, the battle was soon over with the Allies successful.

See also: GIUK gap