I recently shared a cabin with my daugher and 22 month old granddaughter on an 11 night cruise. I thoroughly enjoyed the time we spent together, and had a great time, although the things we did and schedule we kept were different than cruising with all adults. For starters, we ate dinner early, utilized room service more often, and ate breakfast in the dining room instead of grabbing it at the buffet. Reason for early dinner of course is obvious, room service was just more convenient when you just wanted to relax and eat, and having breakfast brought to you in the dining room, rather than fetching a high chair and food in the buffet, was easier. The crew doted on her, especially those that had children of their own, and were do doubt homesick for them.
We devoted a cabinet to her toys, one she could safely open and close by herself, and brought along a few new things. Although a simple roll of blue tape kept her occupied for 30 minutes while we readied for formal night dinner. And no, we didn't use the tape to contain her, but rather gave her small pieces to "stick" on herself and various things. The tape, of course was easy to remove and left no residue.
My daughter and I took turns taking her to the children's club to let her play and run around (an adult needed to be present with child under three). I enjoyed watching her play in the "Little Gym" type envirnoment as much as I enjoyed a show or having a drink in a lounge. We sometimes took her to the early show, or took turns going to the show (one of us would go to the early and one to the late show). Our activities in port had to be geared to something appropriate for her age.
She was more content to sit in her stroller for longer periods of time than normal, both on the ship and in port, since she too was experiencing new sights and sounds. My daugher thought it was little more difficult to cruise with her at 22 months than it was when she was 11 months and not walking yet. But still worth it all the same.
If you're looking for a little "me" time or "couple time" before the new baby is born, consider taking along a grandmother that would love the opportunity to spoil, I mean share quality time with your 22 month old, along on the cruise!