If you have never cruised before, then unfortunately there is likely no way to know in advance if you are going to feel sea sick. I get sick if I look at the ground while walking, but I can be on a cruise ship as long as I want and never feel so much as a twinge.
That aside, if you are on a cruise and are not sure what to do to combat and prepare for sea sickness, then I have some ideas you can try.
1. The patch behind the ear: This is available by a prescription and is known to be very effective. The downside is that it will likely make you drowsy and you do not want to spend your cruise asleep. One possible remedy is to cut it in half, but talk to your doctor about that.
2. The Wristband: There is a wristband that may or may not work. It uses acupressure to relieve nausea, by applying pressure to the right points of the body. The downside is that it might not be effective, the upside is that it will not make you drowsy and you are not using drugs.
3. Over the counter anti-nauseates: Going by brand names such as Gravol, these medications will act the same as the patches but you will take it as you need it. You need to try to take it before you become nauseated. Once you feel sick, they will not help anymore. The downside, like the patches you will spend the rest of the night asleep, the upside is that they are effective.
What are some possible alternatives? Try a natural, non-drowsy, remedy that is available almost anywhere. This is a ginger capsule and is known to be effective for most people and will allow you to enjoy your cruise. In addition, I have found children's gravol to be effective and also non-drowsy.
My favorite thing about a cruise was when I learned how to save 50% on the price of my shore excursions.
You should have the same opportunity to enjoy better, less crowded shore excursions for half the price.