Apple customers have a great opportunity to easily switch their carrier on iPhone 5S and 5c — but in the United States only. The three major mobile operators will work on your new smartphone model because it supports a larger range of radio spectrum than previous iPhones. Here is how U.S. customers can change their iPhone 5S / 5c carrier without unlocking or jailbreaking.
If you live in the U.S.A. and have either an iPhone 5S or an iPhone 5c you can easily switch carriers between T-Mobile, Verizon and AT&T. This instructable will help understand how this works and why your device can support the SIM card of the company it is locked to as well as some other SIMs.This method unfortunately won’t work for the cell phone carriers Sprint and Virgin.
Step 1: Are You Eligible?
You have to activate you device and data plan with the original carrier using a nano-sized SIM. Use only the SIMs created for Apple devices because their class identifier matters.
Step 2: Switch iPhone 5S / 5c to T-Mobile
This is easy. You can simply insert T-Mobile SIM into an iPhone that is locked to AT&T or Verizon, reboot and start using it.
According to T-Mobile, the devices sold in its stores are locked and can be unlocked after 40 days from the time you buy your iPhone.
Step 3: Switch iPhone 5c / 5S to AT&T or Verizon
This is more complicated because both companies use your IMEI and SIM’s ICCID in their system to authenticate your device. Without this, you can’t exchange data but you might be able to use the “voice portion.”
According to Verizon, the 4G iPhones that it is selling are always unlocked.
According to AT&T, the gadgets purchased from AT&T stores are locked but can be unlocked if you call 800-331-0500. If that doesn't help, trusted online factory unlocking sites like this one att-iphone-unlock.com will help you.