A cargo bay or cargo hold is a general purpose storage facility aboard shuttles, starships and starbases. Cargo bays are often equipped with large transporters to assist in the moving of cargo containers. However, aboard Nebula-class starships, cargo bays located in the stardrive section did not have transporters. In that situation, cargo was directed into the bay by a transporter chief operating in a transporter room.

Cargo bays have been used in a variety of ways other than typical storage, including triage centers, brigs, and stasis unit facilities.