17 Port & Maritime Regiment RLC are based at Marchwood, near Southampton. The unit provides the UK Armed Forces' only specialist port, maritime and rail capability and deploys regularly in support of operations and exercises around the world. Soldiers serving as a Port Operator, Mariner, Marine Engineer, Railway Operator or Vehicle Support Specialist would predominantly serve with the 17 Port and Maritime Regiment, though almost any RLC trade has the opportunity to serve with the unit.

The Regiment has three Port Squadrons, a Port Enabling Squadron, a REME Workshop and a Headquarters Squadron. It operates a wide variety of vehicles, plant, railway equipment and vessels, including Ramp Craft Logistic (RCL), Workboats, Landing Craft Vehicle and Personnel (LCVP), MEXEFLOTE rafts and Rigid Raider Craft. It also has the only military Dive Team in the RLC; they are responsible for a range of tasks including port clearance and vessel maintenance.

Due to its unique nature, the Regiment also works closely with the Royal Marines of the Amphibious Task Group (ATG) and often deploys in support of their exercises and deployments around the world.