Saint-Malo is a historic French port commune located in the Ille-et-Vilaine department within the Brittany region. Situated on the English Channel coast, it serves as a subprefecture of its department and functions as a significant maritime hub. The city is geographically defined by its position on the Rance estuary and its proximity to the Dinard peninsula, creating a distinctive coastal setting that has historically influenced its development and strategic importance.

The town traces its origins to a monastic settlement founded by Saint Aaron and Saint Brendan in the early sixth century, with its name derived from the Welsh follower Saint Malo. Before this, the site was known as the Roman Reginca or Aletum. The city declared itself an independent republic between 1590 and 1594, operating as a de facto city-state known for its corsairs. During World War II, the historic walled city was almost totally destroyed by American shelling and bombing in August and September 1944 before being rebuilt over a twelve-year period.

The commune is characterized by its famous walled inner city, La Ville Intra-Muros, which grew up on an island in the Middle Ages. Key landmarks include the Château de Saint-Malo, which houses the town museum and town hall, and the 14th-century Solidor Tower in the Saint-Servan district. The city was fused to the mainland in 1967 when the former communes of Saint-Servan and Paramé were merged into it, creating a unified urban area that retains its historic fortifications and architectural heritage.

Saint-Malo is renowned for its history of piracy and privateering, which brought wealth through extortion and overseas adventures. It serves as the starting point for the transatlantic Route du Rhum yacht race held every four years. The city attracts tourists with its ferry terminals connecting to Jersey, Guernsey, Portsmouth, and Poole. Its cultural identity is strongly tied to its maritime past, including the legacy of explorers like Jacques Cartier and Louis-Antoine de Bougainville, who named the Falkland Islands after its inhabitants.

The population was 47,439 in 2023, swelling to up to 300,000 during the summer tourist season. The metropolitan area had approximately 138,000 residents in 2022. Access is provided by the Gare de Saint-Malo railway station with TGV services to Paris and Rennes, as well as the Dinard–Pleurtuit–Saint-Malo Airport. The region features an oceanic temperate climate with average temperatures ranging from 6.1°C in January to 17.8°C in August, moderated by the Gulf Stream.