When I travel overseas I use a cheap "pay as you go" phone. You can "top up" your minutes in practically any shop or on the internet. I don't use the phone that much so it's only 20 Euro's or Pounds at a time for me. Plus even the cheap phones are capable of WiFi calling so you don't get charged for any minutes when connected that way.If you travel overseas, you can request your carrier unlock your device
My wife calls it my "burner phone."