We went on the submarine with 2 and 5 years old and were very surprised, how much they've enjoyed it. They were really interested to look at all the fishes and the ship wreck. It was a very interesting experience. Wasn't very impressed with the guy at the ticket desk though, didn't feel, he was very friendly. Also they waitress in the restaurant, which they offer you a free drink with a ticket on the submarine wasn't very polite.