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 89 km northeast of Corpus Christi and 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 Bay and Corpus Christi Bay, to the south.
San Antonio Bay is one of seven major estuaries along the Gulf Coast of Texas. The Aransas National Wildlife Refuge is found on the southwest portion of the bay. The diverse wildlife on these shores make up for the lack of a sizable human settlement.
