The private-island day is the one everyone remembers from a Caribbean sailing, and this one is really two islands in a trench coat. One half is a full waterpark with the tallest slide in North America, a wave pool and a zip line, all costing extra and all worth it exactly once. The other half is free with your cruise: beaches, pools, a massive swim-up bar, complimentary lunch spots, splash zones for littles.

Families split the difference well by buying waterpark passes for the kids on a sea-day sale and keeping the adults on the free side under an umbrella. Two logistics notes: chairs and umbrellas on the free beaches cost nothing but the good shade goes before 10am, and the island runs on your ship card, so nobody needs a wallet.

Groups should claim a landmark meetup spot at arrival; the island is bigger than it looks from the ship.