I guess I have to agree with Pat. Our 16 yr old was not as excited about visiting Anguilla as she had been 5 yrs ago at 11yrs. On St Maarten we took our group on a dune buggy tour of the island with Happy Hour Charters (located near the cruise terminal). She didn't think she would like it but DID!! For the most part she was happy just hanging out at the pool, and swimming in the ocean on St. Maarten. She also enjoyed the shopping in Philipsburg.

As far as the boat trip to Anguilla, the roughness depends not the sea. Going over this trip was very rough, coming back smooth! We have done both GB Express and the public ferries and it really is just a matter of the seas at the time. I think going to Anguilla is an amazing experience. So many different things to see that aren't touristy! Driving on the opposite side of the road, snorkeling, the people.

For sea sickness we have used Bonine. This trip we used an oil called Motion Eaze. It gets dabbed behind your ear. Found it on Amazon after a crew member on the Celine recommended it. Worked great!

Good luck and have a great trip!!