Coastal Forces was a division of the Royal Navy established during World War II. It consisted of small coastal defence craft such as motor launches, submarine chasers, air-sea rescue launches, motor gun boats and motor torpedo boats. It did not include minesweepers, trawlers or landing craft. This article is about the equivalent boats used by the Royal Australian Navy (RAN).

Coastal Forces was a division of the Royal Navy initially established during World War I, and then again in World War II under the command of Rear-Admiral, Coastal Forces. It remained active until the last minesweepers to wear the "HM Coastal Forces" cap tally were taken out of reserve in 1968. The division received more gallantry awards than any other branch of the Royal Navy during that period.