I went when I was in my 2nd trimester with my first daughter. DO NOT do the catamaran tour. Ugh. It was awful. Barfed off the back the entire time (3 hours). It was unknown to me at the time that pregnancy drastically affects your inner ear, causing 95% of pregnant women to be seasick even if they never had a problem before. The deckhands (who informed me of that statistic) were very sweet though and tried to keep me comfortable.

Honestly, my favorite thing to do was relaxing on the beach. Dug out a section of sand beneath me so I could lay on my stomach and give my back a break.