San Carlos is a beachfront subdivision within the port city of Guaymas, in the northern state of Sonora in Mexico. It is noted for the exceptional clarity and warmth of the ocean water in its shallow bays. It lies on the body of water known as the Gulf of California or Sea of Cortez. Given the size of the city, with nearly 7,000 inhabitants, there is a remarkable number of RV parks, resorts and stores.