Unlocked iPhone 4 Frequently Asked Questions

unlocked iPhone 4
iPhone 4. image copyright Apple Inc.

In June 2011, Apple started selling an unlocked iPhone 4 in the U.S. At that time, most phones, including iPhones, were sold with a SIM lock, which is software that ties use of the phone to the cell phone company that you buy it through. Unlocked phones don't have this SIM lock, meaning that you can use them on any compatible cell phone network as long as you have a service plan with that company.

Here are the answers to the most common questions about the unlocked iPhone.

Where Do I Buy an Unlocked iPhone 4?
Apple discontinued the sale of the iPhone 4 in September 2013. However, reconditioned and used models are available online.

Does the Unlocked iPhone Include a SIM?
No. You'll need to supply the SIM card, which you get from your cellular provider.

What Is the Size of the iPhone 4 SIM?
The iPhone uses the microSIM format, so request that size from your cellular provider.

Can I Use the Phone With More Than One Carrier at the Same Time?
Yes. As long as you have an active SIM from both carriers and switch the SIMs when you want to switch carriers, you can use multiple phone companies.

Will the microSIM From the iPad 3G Work With This Phone?
No, according to Apple. Though both are microSIMs, the company says that the SIM from the iPad does not work in the iPhone 4.

Network Compatibility
The unlocked iPhone 4 is a GSM version phone, so it is only compatible with GSM and UMTS/HSDPA/HSUPA networks.

The unlocked iPhone 4 is not compatible with CDMA networks.

Use in the U.S.
In the U.S., an unlocked GSM iPhone 4 works on two cell phone company networks: AT&T and T-Mobile. It does not work on Verizon or Sprint since those companies use CDMA networks. While all standard iPhone features are available to users of unlocked iPhones when using AT&T, this isn't the case when using T-Mobile.

Because T-Mobile uses different GSM frequencies for its high-speed 3G network than AT&T, the iPhone 4 can only access the slower EDGE network when connected to T-Mobile. Some other network-specific features, such as Visual Voicemail, also do not work on T-Mobile.

Use Outside the U.S.
These phones were only sold to buyers in the U.S. If you move overseas and can buy a compatible SIM card in your destination country, the iPhone works. Find a local carrier with a compatible network and follow the activation process.

Activating an Unlocked iPhone 4
To activate an unlocked iPhone, you must first have a working microSIM from a compatible cell phone provider. Insert the microSIM and then connect the phone to a computer running iTunes to complete the activation process.

Contract Lengths
Because these phones are unlocked and not tied to any one cell phone carrier, there is no fixed contract length. As a result, you're able to pay month-to-month with whatever compatible cell phone company you prefer to use.

Now That Unlocked iPhones Are for Sale, Will AT&T Unlock My Existing iPhone?
If you're already an iPhone 4 owner using AT&T in the U.S., you may wonder if you can now unlock your iPhone. Currently, it seems that AT&T will not unlock an iPhone 4 purchased through them even if they are out of contract.

Are These Phones Jailbroken?
No. While jailbreaking and unlocking often go hand in hand, in this case, the phones are only unlocked. As a result, while you can use them on whatever compatible carrier you choose, you're still bound to use the App Store and other official Apple systems for software. You cannot install your own apps, like those from Cydia, without also jailbreaking these phones. Apple recommends you not jailbreak your iPhone.