Shirts, Socks, Underwear
The obvious. Of these three I recommend bringing one pair for each day your trip is, plus one extra. Chances are you’ll get sweaty, or spill something, or tear something, or just decide you feel like a mid day change up and it’s better to have it and not need it than need it and not have it
Pants/Shorts and Bathing Suits
Two pairs of each seems like the best bet to me – in case anything happens to the first or if you feel like you need a change
Bathroom Supplies
Don’t forget your medicine, toothbrushes, hairbrush, deodorant, and nausea meds!
Sunscreen, Hat, Glasses
Obvious reasons
A Pair of Nice Clothes
There are nicer restaurants on almost any cruise so it’s helpful to have the option to dress up one night
Plus anything else you feel like you might need. Check out our recommendations for what else you might want to bring that totally aren’t must haves, but we think could be good to grab