If you are planning on doing ruins, nothing compares to Tikal.
As far as diving there, nothing compares to Turneffe. We actually did a day trip to Turneffe out of Amberguis. Long day, but, a beautiful boat ride.
If I was going back to do nothing but dive, I would do the Turneffe Island lodge. Then I would go inland to Chaa Creek again for the inland excursions.
You really need to insist on your family doing the inland stuff. It would be a waste not to.At 13, they may not appreciate it now; but, they will remember it for a lifetime.
I fealt that the inland stuff was the highlight of my trip (Tikal in particular). And we dove a lot.
Enjoy!
Again you are right with regards to the Mayan Ruins Tikal is Spectaqular as far as Turneffe I have to respectfully disagree after diving all 3 Atolls of Belize and many many dives there.
I would put Turneffe at the bottom of the list of Belize Atolls not that the diving is not world class but when you compare it to Ligthouse Reef and Glovers it is clearly in third place.
I would put it in this order based on my experience
Glovers Reef
Lighhouse Reef
Turneffe Islands
Any of these Atolls is absolutely world class diving and neither one will be a let down.
Dive Safe
Gaz Cooper