SD, years ago when my husband and I and other couples we knew were into mah jongg, we purchased mah jongg playing cards, and used them when we traveled. We were able to play in airports, cruise ships, on airplanes -- anywhere. We didn't even need a table, just a common place to put the discarded cards. Sure we missed that dull click of the tiles, but it sure was a portable game when we used cards.
Sandy, thanks for the suggestion. I also put this question on the Princess board of cruisecritic.com, and two people who very recently went on Princess ships, Pacific Princess and Caribbean Princess, said there were mj sets aboard, so I am just going to take my chances. I figure if two ships have them, all the Princess ships probably do.
HeyEliza, that does sound great. I have learned the Regal also has sets, and with 9 of our 15 day cruise being "at sea" days, it will be fun to play some mj. Thanks to you and the others for the good responses.