When an invasion force might carry surface ships

Could large starships carry surface vessels for an invasion?

They could be useful on a largely aquatic world, but a spacecraft is not automatically a submarine because vacuum and deep-water pressure impose opposite structural demands.

Carried surface vessels have a role when a campaign requires access to an aquatic planet's coasts or subsurface environment. A spacefaring hull cannot simply operate underwater as well. Spacecraft are designed against outward pressure, while deep water crushes a hull inward. Basing, landing, and specialised vessel design therefore matter across these different environments.