A cargo bay was an area of a starship, space station, or another type of vessel where cargo and other items were stored. Cargo bays on larger starships or space stations usually also have one or more large transporters for mobilizing cargo.
The cargo bays on a Waka-class starship was located in its saucer section, while the cargo bays aboard the Aotearoa-class, Whakanui-class, and Whakahaere-class starships were located in the secondary hull. (Star Trek: The Cantabrian Expeditions)
In 2373, Liam de Gaillimhe beamed the tracking device the Treaty Killers implanted in Daniel Radke into the USS Aotearoa's cargo bay. Once a Treaty Killers away team beamed into the cargo bay, de Gaillimhe flushed the bay so the enemy combatants were killed. (Star Trek: The Cantabrian Expeditions: "White Flag")
In 2376, Doctor Marie Bourget ordered Retas to take the Merchokan's corpse to the USS Determination's cargo bay, acting as a make-shift morgue, to perform an autopsy as time permitted. (Star Trek: The Cantabrian Expeditions: "Howl")
Also in 2376, Captain Noah Wrightson beamed the Vendoth into the USS Cantabrian-A's cargo bays and turned the temperature down so they went into hibernation so they could be taken to the Steranmio Alliance to face trial for their crimes. Vehayz Ca'l strongly disagreed with his decision. (Star Trek: The Cantabrian Expeditions: "Howl")