The park is separated from the mainland by San Antonio and Espiritu Santo bays and is one of the barrier islands that border the Gulf and protect the mainland from the great tides and strong wave action of the open ocean. Matagorda Island did not exist until about 5000 years ago. The island featured prominently in the growth of Texas in the 1800s. Traces of past activity can be found at civil war trenches, an abandoned Air Force base, and an 1852 lighthouse.

Visitors to the park can enjoy camping, hiking, bicycling, surfing, swimming, beachcombing, and scheduled tours.