La Trinité-sur-Mer (French pronunciation: [la tʁinite syʁ mɛʁ]; Breton: An Drinded-Karnag) is a commune in the Morbihan department in Brittany, in north-western France.

[3] Inhabitants of La Trinité-sur-Mer are called Trinitains.

The town is primarily a port, with a seaside quay dotted by numerous seafood restaurants.

Separated from the well known commune of Carnac in 1864, several of the famous neolithic standing stones in the Carnac stones fall within its boundaries, including the dolmens of Kerdeneven and Kermarquer, and the Petit-Ménec Alignments.

The Pont de Kerisper connects the commune to the neighbouring Saint-Philibert.