Years ago we used to purchase the AT&T cruise option. Now we just use Voom Surf/Stream
We put our iPhones on wifi calling and can call/text our family members as needed, and check emails. We also bring our firestick to watch Nextflix, Amazon Plus etc. etc.
If we're spending time pre or post cruise (out of the country) we use the AT&T international calling then it's for each 24 hour period of time when used.