The Cinque Ports Fortress Royal Engineers was a volunteer unit of Britain's Royal Engineers serving in the defences of Dover, one of the historic Cinque Ports. It provided detachments for field service in World War I and World War II, when they saw active service in Tunisia, Italy and Greece. Its lineal descendant continues to serve in the present day Army Reserve as a bomb disposal unit.

The Sussex Fortress Royal Engineers was a Territorial Force (TF) unit of Britain's Royal Engineers from 1908 to 1920. As well as coastal defence duties during World War I, the unit provided works companies for service on the Western Front.