'Septimus' was a British naval undertaking by Lieutenant P. Williams’s MGB-502 of the 15^th Motor Gun Boat Flotilla to land stores and three agents, and collect five agents at the Pointe de Beg-an-Fry on the coast of German-occupied France (21 March 1944).

The undertaking was successful, the stores and agents being landed, and two evaders as well as the five agents being collected.