The water is clear and visibility is good — no complaints there. But if you're expecting an underwater spectacle, Carabassí isn't that beach.
The seabed is mostly flat sand — clean and pleasant to swim over, but not particularly interesting through a mask. Occasionally you'll come across a small rock on the bottom with a few fish around it, which is worth a look. That's about as exciting as it gets.
For kids snorkelling for the first time — perfect. For anyone expecting reefs, caves, or serious marine life — look elsewhere on the Costa Blanca.
Local tip: If snorkelling is the main reason for your trip,
Cala Cantalar is a better option — rocky coastline, more fish, more to explore.