I bring ALL my scuba gear with me every time I travel overseas. Both my wife and I prefer the comfort of our own equipment. Most tropical destinations will give you shorty wetsuits, and we prefer full. One trip to Cancun we were the only ones on the boat not using vinegar to help with fire coral burns to our legs. And I have had only one problem so far going through customs. I thought for sure my camera bag would get flagged for the multitude of batteries for camera, strobes, and various dive lights, but it never happened. The only thing that did get flagged was my very expensive set of mini tools (screwdrivers, allen keys and mini crescent wrench) that I used to keep in my camera bag to break down my gear, but are now property of the Mexican customs. But they let me keep my nail clippers...go figure! I’ve also never had any of my medicines questions, so I’m guessing your vitamins won’t be an issue. I would definitely take at least your own mask, since it’s not always easy to get a good fit from a loaner. My personal preference is to also have my own fins and booties, since most tropical resorts let you scuba dive with snorkel fins, which tend to hurt my feet. And lastly Sea Sick patches (scopolamine patches prescribed by your doctor) if you need them. Sometimes you can find over the counter stuff like dramamine or bodine. Hope some of this helps. Have fun!