Welcome aboard, Jamie! You've got an exciting cruise on the Disney Fantasy coming up this winter! And since you're sailing in the winter, you have better chances of seeing more waves in the usually calm surf in Tortola and St. Thomas. These islands aren't well known for big waves, but you may find a few!
At that time of year, the waves are more notable on the north shores of these islands, but they can vary day to day, even in the secluded bays. Since
Magen's Bay is on the north of St. Thomas, even though it's a usually calm bay, you may find some small waves there during your visit.
Another fun beach break is at
Baths in Tortola. Even if the waves aren't your kids' favorites there, this beach has these great rock formations and little caves all along the beach that the kids can climb and explore. This is definitely worth checking out!
Now, if your kiddos want to make waves of their own, and they are five or older, check out the
Screamin' Eagle Jet Boat. Now, to be honest, you couldn't get me on that thing! I am not a thrill ride lover, so it's not for me, but I've seen my friends head out on it when we've sailed with Disney and they've had such fun! My son has it on his must-try list for a future cruise!
I hope those point you in a direction to start with, Jamie! Keep in mind that you'll also have the best beach day of them all at Castaway Cay, Disney's private island, so you may consider a non-beach related Port Adventure in one of the other ports instead!
Have fun planning!
Marcy