San Antonio Bay is a bay on the Texas Gulf coast situated between Matagorda and Aransas Bay. It consists mainly of the combined waters of the San Antonio and Guadalupe rivers, and is located at the mouth of the Guadalupe River, about 55 miles (89 km) northeast of Corpus Christi and 130 miles (209 km) southeast of San Antonio. It is protected from the Gulf of Mexico by Matagorda Island, leaving only relatively small and distant outlets to the Gulf for little mixing of bay and Gulf waters. The remoteness of the bay has prevented the establishment of major ports as seen on Aransas and Corpus Christi Bay, to the south.