We cruised a few years back with my niece and nephew who were 2 1/2 and almost 1. They had a great time! They didn't do any excursions that involved driving. But if you did I would say take the car seat. We have 4 kids and 5 grand kids and have done trips with all of them and by ourselves. I personally love the trips with everyone. The little ones are actually easier than the 9 & 7 year olds. ;)