Lydney Harbour sits where the River Lyd meets the Severn Estuary in Gloucestershire, and has served as a working port since at least the industrial era.

Originally the last port on the Severn where sea-going vessels could unload, it grew in importance as a hub for exporting iron and coal from the Forest of Dean, connected to the interior by Pidcock's Canal and later the Severn and Wye Railway tramway.

The inner basin is served by a lock approximately 30 metres long and 7. 3 metres wide, with a depth of 4. 1 metres at the upper gate sill. Leisure craft moorings are available on buoys in the inner harbour, with access to vessels by tender.

Lydney Yacht Club leases premises and a slipway adjacent to the harbour. Today the harbour is also a visitor destination, valued for its views of the Severn Estuary — which has the second highest tidal range in the world — and its rich industrial heritage.

A walking trail links Lydney railway station to the harbour, passing sculptural installations inspired by the Forest of Dean's colliery and shipping history.