Posted May 5th, 2018, 02:32 AM
Another vote for WiFi calling. I used it for almost an hour in Canada where I had no plan. It worked great. Try going to Settings and looking for Advanced Calling. If your phone supports WiFi calling (and, unless it's old, it should) you should find the setting there or in something similar. You will, of course, need Internet access but it's likely much cheaper than using the ship's cell tower.
Also concur with the Vonage option but then I already use Vonage as my wife likes to keep the old landline number that her family called on for the last 35 years or so. I use it over my cable Internet but there is definitely a setup for cell phones with the account. If you have Vonage (I think I pay about $18.50 per month but it makes my wife happy and all political and spam calls go to that number as well as messages from doctors, etc. I don't get hassled on my cell.