I think it’s 12. I’ve had 5 kids in teen clubs at different ages, what I’ve learned is #1, all of my kids hated tween clubs, #2 all of my kids loved teen clubs, #3, 15 - 17 year olds do not want to hang out with younger kids and 12 - 14 year olds don’t want to hang out with older kids, it really works out. On our last cruise my 14, 14, and 16 year olds had 3 different friend groups, as did my 19 and 20 year olds. I think it would be a shame to push the tween club without at least trying the teen club. When my kids were 12 on NCL we just let them go places and let us know where they were going, since they had no interest in the 10 - 12 after trying it.