Any tips on cell phone service in Malaysia?

Hello,

Not sure if you could just slot in any cellphone SIM card when you're in Malaysia, unless your phone is a (GSM) phone "GSM- Global System Mobile. But as what I know (used to lived in USA and owns a Verizon phone) all US phones ate lock phones aka CDMA. Two basic technologies in mobile phones, CDMA and GSM represent a gap you can't cross. They're the reason you can't use AT&T phones on Verizon's network and vice versa.

CDMA (Code Division Multiple Access) and GSM (Global System for Mobiles) are shorthand for the two major radio systems used in cell phones. Both acronyms tend to group together a bunch of technologies run by the same entities. In this story, I'll try to explain who uses which technology and what the real differences are. In the U.S., Sprint, Verizon and U.S. Cellular use CDMA. AT&T and T-Mobile use GSM.

It's much easier to swap phones on GSM networks, because GSM carriers put customer information on a removable SIM card. Take the card out, put it in a different phone, and the new phone now has your number. What's more, to be considered GSM, a carrier must accept any GSM-compliant phone. So the GSM carriers don't have total control of the phone you're using.
That's not the case with CDMA. In the U.S., CDMA carriers use network-based white lists to verify their subscribers. That means you can only switch phones with your carrier's permission, and a carrier doesn't have to accept any particular phone onto its network. It could, but typically, U.S. carriers choose not to.

So maybe you could check your phone if it's a lock phone or a GSM phone.
Hope it helps

Welcome to Malaysia