Possible to transfer an active, Verizon sim card to an unlocked iPhone 8 purchased from the Apple store?
In theory, that would be fine.

When you buy a phone from Apple it will be unlocked for use with any network so they can just put their network sim into it and be good to go.

They both use nano sims so the sim will be good to swap straight away.

The only issue is that Verizon have been using(and AFAIK are still using) a different model of iPhone to the rest of the US networks.

If you're buying it from an actual Apple Store you could ask them just to make sure 100%. As I'm not from the US, I'm not 100% sure what the deal is with CDMA/GSM models as they are all GSM in Europe.

Assuming Verizon still uses CDMA, you would need to make sure that the iPhone is a CDMA version.

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