Jake, I have strong feelings about this. We kept our UK numbers by moving them to the cheapest plan the provider offered, a basic monthly one that allows roaming texts, and both phones live in a drawer except when a bank wants to talk to us. It's not elegant, but it works. Before you port your number anywhere else, check with the bank whether they'll send codes to it. Ours wouldn't send them to some kinds of internet numbers, which we discovered after a very frustrating morning.
ok so I have a very specific first-world-expat problem. my US bank sends security codes by text to my US number. my US number is on a plan I'm paying for purely so I can receive those texts in Mexico. roaming texts sometimes arrive, sometimes arrive 40 minutes later, sometimes never.
i've tried switching to an authenticator app but the bank only allows it for some things, not others (because of course). how are you all handling this? keeping the old number alive on a cheap plan? porting it to some kind of online number? or did you find a bank that's less weird about it?