Oak Island is an unincorporated community and census-designated place (CDP) in Chambers County, Texas, United States.

[2] Oak Island is located on the eastern shore of Trinity Bay, near the geographic center of Chambers County.

It is 8 miles (13 km) south of Anahuac, the Chambers County seat.

According to the United States Census Bureau, the Oak Island CDP has a total area of 1.20 square miles (3.11 km2), all land.

[15] As of the 2020 United States census, there were 371 people, 135 households, and 126 families residing in the CDP.