My 11-year-old son absolutely loved AC, especially snorkling at Hol Chan, Shark/Ray Alley, and near Mexico Rocks. His favorite by far was snorkling with sharks, sting rays and spotted eagle rays (which we did with a guide -- can't recall his name -- who works out of Journey's End resort). I would suggest bringing masks for the kids --we had difficulty finding them for my son, who is very small. I'm sure he would have loved reef fishing, but we simply didn't have time to do that. My daughter did not enjoy snorkling as much (the fish were too big!), though she did like swimming in the pool. She is a typical teenager (ugh!) and her favorite spot by far was the cybercafe on the main street. She is extremely social, and except for befriending one native girl, she didn't meet any other kids to hang around with (there were no other teens at our hotel that week). We did take two trips -- a manatee watch, goff's caye, caye cauker excursion -- highly recommended! The other trip, to Lamanai, didn't hold our kids' interest too much.
Yes, we let them walk around by themselves a little in San Pedro during the day, but they are used to a lot of independence, as we live in NYC and they walk everywhere themselves. My daughter was approached by lots of native guys, mostly older, but we were always around and she was able to handle herself quite well. They also weren't threatening in any way.
We also didn't rent bikes, but we did rent a golf cart one day to explore the island.
Feel free to email me directly if you have more questions.
[This message has been edited by susanhope (edited 05-26-2000).]