Hi, not sure on when you were last there, but we took 14 and 15 year olds 3 years ago, and had possibly the best holiday of our lives. The girls loved the Caretta fun park which opened around 6pm I think, although peak season is possibly all day. They spent a day at the water park which I think was 10 or 15 euros. Not bad for a full day of water filled fun. We went to the crazy golf, which was good fun and had a ride in a horse and carriage. I don't think that keeping them entertained and busy will be a problem. It all depends on your budget I suppose. Enjoy!!