Diano San Pietro is a comune, or municipality, situated in the Province of Imperia within the Italian region of Liguria. It is located approximately 90 kilometres (56 mi) southwest of Genoa and about 6 kilometres (4 mi) northeast of the city of Imperia.
The town serves as a local administrative center in the coastal area of the Riviera di Ponente. Its geographic position provides it with proximity to both major regional hubs and the Mediterranean coastline.