It passes through the town of Los Alamos, California and downstream flows through Vandenberg Space Force Base.

The lower course through Vandenberg SFB has a perennial flow, in part because of irrigation tailwater, but primarily because of a geologic rift at Barka Slough which causes an upwelling.

The principal crops grown within its watershed are vegetables in the flat fields, and winegrapes in the transitional upland slopes.

[3] West of Barca Slough, San Antonio Creek is inhabited by the endangered Unarmored Three-spined stickleback (Gasterosteus aculeatus williamsoni) which, for all practical purposes, prohibits any stream maintenance.

[3] The first European land exploration of Alta California, the Spanish Portolà expedition, camped near the creek on August 31, 1769.