As a CDMA-based carrier (until LTE takes over), Verizon isn't nearly as friendly to the bring-your-own-phone trend as the likes of AT&T or T-Mobile. You can't usually swap SIM cards and expect your unlocked phone to work. Thankfully, the carrier recently made the process a whole lot easier... provided you have the right device, that is. It'll now activate compatible, unlocked versions of the iPhone 6 and Nexus 6. So long as you can find your device's ID and pick up a Verizon SIM, you can jump over to Big Red without having to ditch your existing hardware. You'll likely be stuck if you own another device, but that's more due to technology (few unlocked phones have full Verizon CDMA and LTE support at present) than anything else.