The bay hosts a valued ecosystem for the endangered whooping crane, and is a prime location for birding and fishing.

Goose Island State Park and the Aransas National Wildlife Refuge are located along the bay's shores, attracting nature enthusiasts year-round.

[2] The name derived from a Spanish vessel that was being used to transfer money to Texas to bribe Mexican soldiers at Goliad and San Antonio in 1818.

[1] St. Charles Bay is shaped laterally from south to north, and is located on the Texas Coastal Plain between the Lamar and Blackjack peninsulas.

Further north, past a large tidal swamp, Egg Point juts into the bay, above which an inlet forms the Bill Mott Bayou.

Past the Mille Dietrich Point, the McHubb Windmill and Bayou are found, as the bay narrows in width.

From there, the shore forms a straight line southeast to the Big Sharp Point, from which a gas well can be seen in the bay.

[6] The endangered whooping crane, the largest bird in North America, is the most highly prized sight as only a few hundred remain,[7] including three families on St. Charles Bay.

The population increased following the organization of the Aransas Migratory Waterfowl Refuge in 1937,[7] after the Federal government purchased the land of the St. Charles ranch from San Antonio oilman Leroy G. Denman, using funds from commemorative stamps.

[7] Thirty seven species of mammals are found on Blackjack peninsula, including white-tailed deer, nine-banded armadillos and collared peccaries.

[12] Today, due to the bay's location, east of Goose Island State Park and west of the Aransas National Wildlife Refuge, very little industry can be found.

[13] The lack of coastal winds also attracts tourists interested in kayaking and wade fishing,[11] however, boating is hindered by the general shallowness of the bay and the abundance of oyster reefs.