Talk:Thailand/@comment-33932677-20171211100419/@comment-24682153-20171211155731

Hi. Almost all SIM cards in Thailand are 4G-enabled now. It's hard to find an old 3G SIM. But normally 4G-SIMs are downward compatible. This means they work in 3G devices as well, just not on a 4G network, but in 2G/3G-only. I can't really imagine that an old iPhone can't cope with a new 4G SIM.

When you are in Bangkok, I'd go with a problem like this to their IT warehouse / electronics mall of Pantip Plaza at Petchamburi Rd. There you might find an old SIM or a new one that fits too.