During the 11 years I lived in Galveston, I tried local diving numerous times. I couldn't afford to go offshore due to medical school. My in-laws lived on Offatt's Bayou and had a dock off which things would occasionally get lost. None of them ever got found, except a largish anchor which I kicked after giving up ever finding it. Visibility was usually around a foot or so. The beaches are fairly nondescript sand out farther than you can stand to swim. Because the bottom slope is so shallow, waves kick up sand way out. I really wanted to find some local place to dive, but couldn't. Sorry.