Some parents buy inflatable things to covert the shower to a bath.

They usually have a mid week sale on laundry — I washed all the gross stuff the kids have that way — you just shove it in a big bag. (Don’t put in anything nice—they basically boil it.).

Agree on little things they can play with at table. Those Melissa and doug removable sticker things — eg dress the doll, animals in different habitats, etc. , are great. Although I guess nowadays you can also just hand a kid a phone to play with while waiting for food.

Benadryl works for motion sickness in little kids but will make them sleepy. They probably aren’t old enough for Bonine but I might cheat on the older kid if the motion sickness is bad.

If you have magnetic hooks or even just big magnets I find those helpful—the walls are metal so you can stick things on the wall the help get stuff off counter space.

And here’s something truly optional—on my first cruise with a toddler I brought a dark shower curtain and a bunch of magnet hooks to hang a divider down tje middle of the room so she couldn’t see me from her bed. If she saw me, she’d want to get up, but if she didn’t see me, she went back to sleep.

I also brought sleeping clothes that I could wear around the ship. If my little one work up and I didn’t want to wake whoever else was in the room, I could just grab her diaper bag and stroller and take her out before she work anyone. I think I kept a bra in her diaper bag. We would change her diaper in the public restroom then hit the buffet for coffee and a snack then do laps around the promenade deck until others work up. It was good exercise for me and kind of nice to be able to walk around a bit before the ship was crowded.

Are you doing laundry? If so, get some laundry detergent sheets to bring along.

+1 to activities for during meals. We recently were on a cruise with my 3 and 5 yo niece and nephew, and mealtimes were tough. They were long and my BIL and SIL didn't bring anything for them to do (no books, coloring, anything). This was a smaller ship and the crew caught on to bring the kid meals early, but they didn't bring either of the parents' meals early...so instead of the kids acting up before food, they just acted up afterward.

A friend of mine asked for restaurant activites for her 3 yo for Christmas, I got her a pack of My First Hidden Picture books which look fun:
https://www.amazon.com/gp/product/B092NRBYWN/ref=ppx_yo_dt_b_asin_title_o01_s01?ie=UTF8&th=1

One day on our ship, I found a Jenga game that my niece and nephew liked building with...I think there is a Travel Jenga you can get. Which is obviously for the room and not the dining table, lol.

PPs have covered most of it. Water is surprisingly hard to access. Consider buying a 12-pack on the way to the port and checking it to your stateroom along with your suitcases. You'll need to print a luggage tag and bring tape to affix it to the case. Bring reusable water bottles to the fitness center for the easiest refill - they use pitchers in the dining room, which is hard to pour into some bottles.

Bring enough diapers & wipes for the entire trip. You'll pay triple the cost at the onboard store for those, sunscreen, Tylenol, etc.

Portraits are a big thing on ships. They're always taking your picture and trying to sell the prints to you. There's also a well-lit studio. Could be an opportunity to handle your Christmas card photo.

wixsticks or similar. small coloring books/pkgs from the target $1 section. Bring them with you to mealtimes at the resteraunt.

also, bring nighttime books for the kids and a few small toys they like (when we traveled with a 5 year old, we took a small ziplock bag of cars, for example. Played with them in the room).

Kids medicines - for fevers, cuts/scrapes, tummy aches/throwing up, thermometer. A sweatshirt and warm pjs b/c sometimes the rooms are cold at night. Card games in case internet is out (or you're not paying for it) and the weather is bad that you can't swim/be outside. Pre-packaged snacks, water bottles to refill, a nightlight - inside cabins are very dark at night, a shoe rack to organize everything, magnetic hooks for the wall to hang stuff like wet bathing suits, jackets, etc.

Heading out on a cruise with my young kids - 2 and 5 - next week. First time taking them on a ship. Any must haves I should pack?

We’re going on celebrity, so a nice ship that has some programming for kids, but not designed for young families.