Yes there phones can be used overseas....but check with Verizon on what you need to have.
How good is Verizon in the UK??
I have used Verizon in the past. Their phones have limited usage overseas and they LOCK the phones. That means that if you are abroad for an extended period, you can either pay their high roaming charges or you have to be a new phone. You cannot use a VERIZON phone with another provider. Further, Verizon is rather deceptive and confusing about their plans and it is very easy with them to incur charges accidentally.
I rate them at the bottom of all service providers.