Port St Mary is located in the south-western part of the island, near Port Erin.

A railway station is just north of the village, one of the stops on the surviving section of the Isle of Man Railway between Douglas and Port Erin. Steam trains operate on the line several times a day during the summer season, and stop at Port St Mary. The village is served by Bus Vannin services to Port Erin, Castletown, Douglas and Onchan.

Once a fishing and trading port, the village is still popular with tourists and fishermen, especially during the summer. The inner harbour, with its pier created in 1812, is tidal and dries out from half-tide. The outer harbour, created when the Alfred Pier was built in 1882, is accessible at all tide states - unique amongst the Manx ports. The Royal National Lifeboat Institution has had a lifeboat and station in Port St Mary since 1896. The current lifeboat, the Gough Ritchie II, lies to a permanent floating mooring inside the outer breakwater.

The village is home to the Port St Mary Golf Links, the Island's sole 9-hole golf course, and also Scoill Phurt le Moirrey, a primary school opened in 1993-1994. The Isle of Man Yacht Club is also based at Port St Mary harbour.

Chapel Bay, a sandy beach in the upper part of the village, is used for recreation and bathing in the summer months.