Beaches down south are nicer, but Galveston Island beaches are almost OK in the summer when the sand dries out.

It's the water that's variable. It's blue - green further off coast, but it varies how close the blue line comes to the beach. Every once in a while in looks very nice, but most of the time water is brown right at the beach and within a few hundred feet.

For most hotels on the Seawall you will have to cross the street to go to the beach, but it's no big deal.

Don't forget about the free ferry to Bolivar Peninsula. Chances are you will see dolpins swimming along the ferry. Car lines can be long in the summer, especially on weekends, but you can park by the ferry landing and just walk on for the (IMHO fun) ride.