The crafts which dock at the port are mainly local fishing vessels, naval ships and luxury yachts; warships routinely visit the harbour.

The harbour is located at the mouth of the River Dart (the name 'Dart' is Brythonic Celtic meaning 'river where oak trees grow'),[4] which rises high on Dartmoor, and enters the sea at Dartmouth.

[7] Blackstone rock, 8 feet (2.4 m) above high water level, is a landmark for ships to bypass shoals at the entrance.

Entrance to the bay is 220 yards (200 m) wide between the rocks but as it widens into the harbour it provides enough room for vessels of any draught and fairly large capacity to berth safely.

Up to the minute tidal information is available from Dart Harbour administration, based on UK Hydrographic Office data.

[8] The light provided on the 85 feet (26 m) tower (above high tide), as of 1871, could be seen over a distance of 11 miles (18 km) in clear weather.

After passing through the channel between Castle and Kettle points, the fixed light provided at the guard station at the southern end of the town guides ships into the anchorage through the fairway.

Good quality produce is available, with some of the best shellfish areas in the whole of the UK, as well as Sharpham Vineyard and Cheese Dairy (for the best of wines), and a hot air balloon over the nearby countryside.

The castles once operated a defensive chain across the estuary, which was raised at dusk to block enemy ships attempting to attack the harbour.