Sant Carles de la Ràpita is a coastal town in Catalonia in the comarca of Montsià (Tarragona province). It is located south of the Ebro Delta and has 14,789 inhabitants (as of 1 January 2019). The municipal area has a size of 53.7 km².

Sant Carles got its name in memory of a convent that existed at that time. The town has Arabic roots, but was founded as a town by King Charles III in 1780 with the aim of developing it as a trading base for America. Over time, Sant Carles has been rebuilt in a neoclassical style and has become an attractive coastal town.

The town is known for its production of rice, salt and seafood. The large fishing industry, specialising in mussels, prawns and shellfish, is an important economic mainstay for the region. In the harbour, you can watch the unloading and auctioning of fresh fish every day. Rice cultivation and salt production take place mainly in the Ebro Delta. In the last 10 years, tourism has taken on an increasingly important economic role. As part of this development, the number of boat moorings has increased, and the catering and beach infrastructure has improved.

The average annual temperature in Sant Carles de la Ràpita is 17.0°C. In a year, the average rainfall is 539 mm.

Catalan is the predominant language spoken in Sant Carles. However, Spanish is also understood and spoken. Young people now also speak some English. 

Sant Carles became famous because of the Los Alfaques tanker accident. Here, on 11 July 1978, a serious accident involving dangerous goods occurred on the then national road Carretera Nacional N-340 in the area of the Los Alfaques campsite, 2 kilometres south of Sant Carles. 217 people died, at the time, and more than 400 people were seriously injured. To this day, a memorial plaque in front of the campsite commemorates the dead of the accident.