Originally Posted by transpac

People, including the OP, seem to be conflating "verification" and "alerts".

Every FinServ company has different verification procedures: personal questions, SocSec, number reco, voice reco, token, OTP via SMS, email etc. For each company, it is best to research the options and plan accordingly. Drill down on any SMS procedures. And different procedures (transfers, bill payment, wire xfers, etc.) may require different verification options. ATM usage does not require verification, but it might result in some alerts.

Before moving to Thailand there is a whole checklist of items to cover, including telecoms and your various financial services companies, incl. credit cards. It may be simplest to port out an existing mobile (or fixed line) number from a post-paid service to a reliable pre-paid service. Then you don't have to change numbers at the banks. Obviously, verify international roaming partners and procedures before leaving. For now, T-Mobile seems both reliable and cost-effective (~$36/year plus local sales tax). but this plan may have some international limitations so research this well before committing. I would avoid MVNOs but that's just me. Who knows if a Ting/Verizon CDMA SIM will roam in Thailand in 2020? It should, but the transition might be rocky.

Alerts can come via various means: email, SMS, app. Some of these simply require a data connection (WiFi or mobile data) while SMS requires a roaming signal (unless your provider supports WiFi calling - some in the U.S. do, DTAC supports WiFi calling here, and it works well for me when traveling). Apps, and other mobile devices (tablets, notebook PCs), should be registered on the device before leaving the U.S.

Also, remember to set up standing wire transfer orders in person before leaving. AFAIK, Schwab offers fee-free SWIFT transfers, but not sure how these are initiated? I'd recommend a Bangkok Bank account be set up in the foreigner's name ONLY, but this does some present some logistics issues as the account must be set up first. Open the account in a branch closest to where you think you might reside, and consider a mall branch as these are open extended days/hours, even on some holidays.

You will probably need a VPN in order to access some/all of the sites so make sure you sort that out as well.

Just recently even T-Mobile requires an SMS OTP just to manage my account, although they do offer the 3-question option, but set that up before you leave.

Definitely get a Google Voice number before leaving. I'd also recommend Talkatone, free as well.