This was the most boring excursion we have ever done. I felt disheartened at spending $310 USD for two and we wanted to return by taxi after realizing what it was like, so that we didn't waste half a day away from the resort and beach.
If you have never been snorkelling before or swimming near nurse sharks or stingrays, then you will probably really enjoy it...it is a nice outing if you are new to these things or get sick on long boat rides, because it is only a few hundred metres from the marina. But if you scuba dive or snorkel often, then do not do this excursion. There "reef" there is mostly dead (unsurprising, with all the boats and traffic there) and very little to see except what is in captivity. I felt so sad for the large stingray swimming against the net...and you have to wear a float belt at all times in the water, which means you can't dive down to get a closer look at anything. And visibility is very poor, so it is difficult to see more than a couple of metres away. It was nice to have activity options and if you don't have the opportunity to kayak or paddleboard at your resort, then I suppose this is a good chance to do that. This is a definitely a touristy place, so just know what you are getting into,