Sant Carles de la Ràpita is a town in the area of the Montsià in Catalonia, Spain. The town covers a portion of the south-west of the Ebro Delta, including el Trabucadoristhmus and la Banyapeninsula, which close off a salt water lagoon known as the Port dels Alfacs. The town of Sant Carles de la Ràpita is situated on the coast near the mouth of the lagoon. It was founded by Charles III of Spain as a port to serve trade with the Spanish colonies, and constructed in the neoclassical style of the period. However, much of the town remained uncompleted after Charles' death.
Sant Carles is part of the Taula del Sénia free association of municipalities. It is known for the production of rice and salt, and is also an important fishing port, particularly for shellfish and prawns, and a tourist centre. In the last few years, the town has suffered a huge urban development due to the construction of many apartments and residential buildings.