If it is an iPhone 5 or later that was made specifically for the Verizon network, you do not need any special codes.
If it is an iPhone 4S you may. The iPhone 4 on Verizon's network was limited to CDMA capable networks abroad and does not take a SIM card. Also, if it was previously on another network you would have to check with that network.
@deloused Making sure your device is compatible while traveling is important. Please clarify the following question. Is this a Verizon phone? Where did you purchase this phone from?
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