Can you try searching for networks manually and there select Verizon, T-Mobile or AT&T in the list. Verizon should be the top choice, followed by T-Mobile.
You can also test this & if you have the opportunity to connect somewhere to wifi with the internet. And check if you have a system update to do. If so, do it, and be ready with your pin code.
Under Network mode, select 3G only. And test that .
It's always good to make sure you have the latest software.As well as apps in the playstore. As apps are also relevant to Android's functions.
https://community.tre.se/utland-36/gaar-inte-att-ringa-eller-ta-emot-samtal-i-usa-5208
Keep in mind if you are going on a cruise, they may have their own mobile network via satellite which can be expensive when the mobile connects to it, and good to avoid. So a good Wi-Fi wireless network is good to find when you are out on a trip.
Also to preserve your surfing pot, so it doesn't run out too soon. So Wi-Fi is great to use as much as you can.
/F