I swear you can really do this- well I did it and it was awesome!
Last summer we took a cruise with a 15 month old. She was not old enough to use the kids programs yet, and couldn’t go in the pools because she wasn’t potty trained. Which needless to say left us with not a lot of entertainment for her and even less entertainment that would allow us to be semi relaxed at the same time.
So we bought a 24” inflatable pool to use on the ship. Well we actually bought 3 different pools while I was trying to figure this all out in my head ahead of time. But the 24” was eventually what we used. I really thought it would be too small, and while it sounds too small to say it was only 24” across in fact it was perfect.
I, being very concerned about whether or not they would actually let us do this and whether or not it would actually work, scouted out the pool area to find just the right spot for us. I was able to find an area right next to the shower and near a drain; which also based on the layout of the ship and pool allowed us to box our 15 month old in between our 2 lounge chairs and the bench seat that ran the edge of the pool. Corral complete all we needed was some entertainment.
Because it was so small it only took 2 minutes to blow up. I then asked the bartender to borrow a bucket, (that they use for their buckets of beer), and to have a few plastic cups. We filled the pool up from the shower, and she was in heaven. We actually ended up keeping the bucket which only added to the fun of sitting in the pool and filling the cups with water and dumping the water in the bucket, and repeat 700 times. Then we built things with the cups, and then we used them to dump water on daddy; she was totally content with minimum entertainment needed from us. It was the best of both worlds.
FYI – No (US) cruise lines allow any type of diapers or swim diapers in the pools. Even if they sell swim diapers they are for excursions not for the pool. Also, it was a Norwegian Cruise Line cruise that we used our inflatable pool. I never asked permission, (for fear I would be told no), but the staff clearly was aware of what were were doing and never raised an objection. Happy cruising!