Some attractions I think your kids would love – there is a museum called the Oceanographic Museum which has a huge 2 floors full of aquariums – there are sharks, massive fish, jelly fish. It’s mentioned. The zoo is really good. You will find this not far from the Princes Palace.
Also there is a zoo ‘Jardin Animaliar’ is pretty good also. That is on the other side of the harbor.
The larvotto beach is good for swimming and during the summer you can hire jet skis, etc. Also no beach in Monaco is obligatory topless but a lot of people do go topless.
There is a pool right on the main street downtown that you can pay to swim at and when were there were some carnival type inflatable jumpies that they could go in right by the pool. They loved looking at all the huge private yachts in the harbor (as did I). There is a Japanese garden with bridges and fish that they would like and just walking around.
For the casino there is limitation to the entrance of up to 18 years.