Oso Bay's sea floor consists of mostly mud, ooze, and oyster reefs, which is discouraging for swimming.
The depth of the main bay and an old, abandoned railroad structure along with the abundance of oysters and vegetation promote fishing.
Birding and hiking are popular activities along the wildlife refuge on the North shore of Oso Bay.
Oso Bay is home to the Hans and Pat Suter Wildlife Refuge which is considered to be one of the best sea bird watching areas in the world.
Some of the birds regularly found in the on and around Oso Bay are: pelicans, herons, seagulls, coots, egrets, spoonbills, skimmers, and ducks.