Marinas don't headline trailers, but they're consistently among the most-used parts of any GTA 6 map. Trailer 2 has marina frames - quieter, wealthier coastal stretches with yachts at moor and small boats moving in and out.
This piece focuses on the marina-coded parts of Vice City. For the industrial waterfront, see the port district piece.
What the marina frames show
Yachts. Smaller pleasure craft - cruisers, sport-fishers. Jet-skis on trailers and on the water. A wooden boardwalk along the seawall. Palm trees, restaurant exteriors, the kind of waterfront that exists between the strip and the residential beach blocks.
Visual coding is leisure, not industry. Different from the port district in lighting, density and architecture.
Where the marinas sit relative to the rest of Vice City
Plural - probably more than one. Trailer aerials suggest a marina close to downtown on the mainland side, plus coastal mooring on the barrier island near the art deco strip. The wealthier mansion zones likely have private docks adjacent.
The marinas also probably extend out of the city itself - the bridge route toward the Keys starts from somewhere, and a southern marina would sit near that transition.
What marinas are likely to be used for
Boat acquisition. Side-content fishing or smuggling (speculative, history-based). Story missions involving boats. Photo locations. Recreational coastline cruising. Probably the entry point for some of the boat routes across the wider coastline.
Historical comparison: GTA V's marinas served boat-related side content and one or two main missions; the wealthier marinas were access points for high-end vehicles. Same pattern is plausible here, scaled to a more boat-rich map.