Just noticed a cruise video where Norwegian Cruise Lines have banned walkie talkies, and this seems to be more common now!
video here
That’s a bummer. I’m guessing that will include handheld scanners as well, because the security folks probably don’t know and don’t care about the difference.
I bought my son and new wife a set of GMRS radios just for that use earlier this year. They were headed to SE Asia and Japan so they wanted to be able to keep in touch without messing with SIMs for each area. I hope you can still pack them for emergencies.
GMRS radios use US frequencies. Japan and Asia may well have other services on these frequencies - so depending on which Asian country you are in, you could get in plenty of trouble - or none. As a Brit, I took some cheap walkie talkies to the US, and in the mountains they were fine - but only when I got home did I realise that our UK frequencies in 441MHz are not very US friendly. I’ve taken them to the UAE too - and again, that’s potentially trouble!
I checked Japan sources and found this:
Q33
Aren’t FRS and GMRS illegal?
A33
FRS (Family Radio Service) and GMRS (General Mobile Radio Service) are both manufactured according to US standards. Since these are radio equipment (transceivers) that is sold exclusively for use in the United States, their use in Japan constitutes an infringement of the Radio Law.
(Using FRS and GMRS equipment in Japan could cause interference to broadcast station radio as well as fire radio and disaster prevention administrative radio.)
FRS and GMRS radio equipment does not have the Technical Conformity Mark affixed. Please do not either purchase or use such equipment.
I don’t think they ended up using them much if at all. They were on their honeymoon so they weren’t separated very much I’m assuming. 
I did warn them to check local laws before hand.
Back in May 2023, we booked a cruise to Alaska with Norwegian Cruise Lines. I knew they banned “ham radios”, so I planned on just bringing FRS/GMRS radios. I thought they might be useful for keeping in touch throughout the ship. I have some FRS radios that can be set to vibrate for an alert and I also have some GMRS radios that can pair with a smartphone and bluetooth earbuds, so I could communicate with family members without using the radio’s speaker, to be less irritating if we were at a meal, or something like that. They also have the capability of sending text messages over the air via the smartphone app. So, we could just text each other discreetly, without needing a cellular connection.
I was disappointed when they added “walkie talkies” to their list of banned items, this past Summer. I guess we’ll just have to pay the fee for messaging through their app while on board.
As someone with both an amateur radio license and a GMRS license, with multiple scanners, and HF receivers, I like to know that I have some sort of option for comms in the event of a disaster. I don’t like that I have to leave most all of my tools at home, but I suppose this will free up space for another camera lens, or a monocular, or first aid supplies, sunblock, etc.
I’m still contemplating the thought of bringing a scanner with me, but I probably won’t risk it.
I suppose it’s understandable - clearly, in international waters things are OK, but with even Canada and the USA having different rules, let alone every country - it would be easy to have a legal system operating illegally. If you have to use you phone wirelessly and pay for the wifi access anyway, then zello might work for you - it wouldn’t be a walkie talkie and break their rules, but work like one - and they’re frugal with data too?