There is not much storage on a yacht. Therefore, we recommend not to take suitcases (non-folding), but travel bags with you. Normally, people take too much with them. However, you will wear mostly shorts, t-shirts and swimsuits. For the colder evenings, you can take a sweatshirt or a thin jacket. For the early and late seasons, you might need some thicker clothes for the evenings as humidity increases when the sun sets.
Don’t forget sunglasses, sunbathing towel, CDs, camera and swim gear, and think about seasick pills. On board the yachts, there are snorkel & flipper sets for usually adults. In case you come with children, take their own snorkel set.