Situated on Romney Marsh, St Mary's Bay has a long sandy beach which stretches north to Dymchurch and south to Littlestone-on-Sea.

Also at St Mary's Bay was the Sands Holiday Motel and accompanying Bahia Bar, sited on the seafront roughly opposite the turning to Jefferstone Lane on the A259.

Known as Pirates Spring and located on Coast Drive close to the beach, the home was run by the National Society for Mentally Handicapped Children (now Mencap) and had the actor Brian Rix among its patrons.

During the 1970s St Mary's Bay had a small supermarket situated at the top of Jefferstone Lane opposite the previous Post Office site.

'The Bay' was host to both a butcher's and a baker's, but both are gone now; the site down Jefferstone Lane had houses built on it in the late 1980s in a development named Old Bakery Close.

'The Bay' is the home to an Army Cadet Force Detachment, located down Jefferstone Lane just over the RH & DR railway crossing adjacent to a caravan park.

St Mary's Bay has a modern village hall located opposite the site of The Bailiffs Sergeant pub on land that was originally part of the School Journey Centre holiday camp.