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Everything you Need to Know About Carriers and Unlocking

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You may have a lot of questions about your cellular network (3G or 4G) providers, or perhaps questions about unlocked iPhones or iPad - questions which this article can answer.

About Carriers
Carriers offer cellular connections (3G/4G/LTE) so you can get Internet when you are away from Wi-Fi, as well as phone and text messaging.
In the United States, the iPhone and iPad can be purchased on an AT&T, Verizon, Sprint or T-Mobile network

When you purchase a phone on one of these carriers, it is usually locked to that carrier, which means that you can not use it with a different carrier. Additionally, when you buy a phone from one of these carriers, it usually requires a 2-year contract, meaning that you must pay a monthly 
service fee for phone, texting and cellular data. If you choose to end this contract before the two-year period, you will need to pay an early termination fee. Note that even if the contract is terminated, you still can only use the phone with that carrier. However, once the contract is over, you can ask your carrier to

3G, 4G and LTE
The iPhone 4S can support HSPA+, a type of cellular connection which AT&T and T-Mobile consider to be 4G speed. Starting with the iOS 5.1 update, the network indicator will show when you are on 4G. The new iPad (3rd generation) is the first device to feature LTE, 
the fastest kind of 4G available at this time. The iPhone 5 and later also have LTE capabilities, as do the iPad mini and later versions of the 9.7-inch iPad.

Unlocked Devices
If you plan on using different carriers, the only way to get a phone that works with any GSM carrier is to purchase a factory unlocked iPhone. 
This iPhone will work with any GSM carrier and does not require a 2-year contract. This model of iPhone is much more expensive, starting at 
$649 for 16GB (iPhone 5S). A carrier will sell you an iPhone starting at $199 for 16GB (iPhone 5), but this is because it is locked to that carrier 
and they can easily make tons of money off of you from the 2-year contract. Unlocked iPhones can be used with any GSM carrier, which you 
can read about below, and still need a SIM card to be activated. The unlocked iPhone does not come with a SIM card, so you will need to get 
one from the carrier of your choice. Note that you cannot use an iPhone without activating it first, which requires a SIM card. The iPhone 4 and 
4S use a Micro SIM, which is a lot smaller than a SIM. The iPhone 2G, 3G and 3GS use SIM, so a Micro SIM from a 4 or 4S cannot be placed
in older models, and vice versa. The iPhone 5 uses a Nano SIM, which cannot be placed in older models.

"No-Contract" phones, though they are the same price as unlocked, do not come unlocked. No-Contract means that the phone can only be
used on a single carrier, but you are not tied to a contract or two-year agreement. However, AT&T should unlock a "no-contract" phone if you
complete their unlock process (and can do so here:, because their main requirement is that the contract is completed.

If the phone was unlocked by any hack or modification to iOS ("jailbreaking"), updating or restoring the phone would re-lock it to the original 
carrier it was locked to. If you are purchasing an "unlocked" phone from a source other than Apple, be extremely cautious when buying and 
make sure the phone has not been hacked. The only way to be certain of this is to buy directly from Apple. If you have a hacked phone, you 
would be unable to get any type of support or repairs from Apple, which is another reason to be extremely certain that the phone is not hacked before you buy. Do not attempt to hack your own iPhone, as it will not work properly and can cause permanent damage to your iPhone. There
are no third party websites or shops that are authorized to unlock, so do not trust these shops with your serial or IMEI numbers. They will hack 
your phone or hack your carrier's servers and claim it is unlocked. Your phone may work on other carriers, but not always if the phone was hacked. Any attempt to restore or update the operating system on the phone will cause it to re-lock if illegally unlocked by a third party service. A 2014 law allows the use of third party unlocks, but only if the contract is completed. Even if your phone is off-contract, third party unlocking services can be untrustworthy, and most carriers will unlock a no-contract phone anyway.

If the phone was legitimately unlocked, meaning you got it out-of-the-box "factory" unlocked from Apple or your carrier unlocked it, it will not 
re-lock. You can update the software, upgrade to a newer iPhone, whatever you please, and it will not re-lock.

If you have a locked phone, it is possible for the carrier to unlock it for you after completing a contract or paying an early termination fee. Apple cannot unlock it for you. The only way to get it unlocked is through the carrier the phone is locked to. Some, not all, carriers outside of the U.S. 
will unlock phones after a certain amount of time, or different criteria. Carriers are not required to unlock after your contract. If you do not 
wish to start a new contract, you can still get Internet through Wi-Fi, messaging through iMessage (requires Wi-Fi, in this case, and iOS 5 or 
later), and phone calls through using FaceTime Audio, or an app like Pinger or Skype.

In the United States, there is not much benefit to having AT&T unlock your iPhone unless you plan on traveling to a different country. AT&T is
the only major supported GSM network in the United States aside from T-Mobile, and unlocked iPhones only work on GSM carriers.

The below Apple link will help you find a carrier near you, as well as find out if your carrier allows unlocking.

Corresponding Apple Article: (will take you to Apple's website)

If you don't know what carrier your iPhone is locked to, call 1-800-APL-CARE (1-800-275-2273) in the United States. Be sure to have the
serial and/or IMEI number ready (this information can be obtained from Settings > General > About).

About GSM and CDMA
GSM - Global System for Mobile communication
CDMA - Code Division Multiple Access

GSM carriers use SIM cards to access cellular networks. SIM cards are also required to initially activate the phone. If you buy an unlocked 
phone, it is designed to work with any GSM carrier. In the U.S., AT&T and T-Mobile are GSM carriers, and about 80% of carriers worldwide are GSM carriers.

CDMA carriers do not require a SIM card to use their network, as there is an internal card. In the U.S., Verizon and Sprint are CDMA carriers,
and about 20% of carriers worldwide are CDMA carriers.

The iPhone 2G (original iPhone), iPhone 3G and iPhone 3GS are GSM only, and cannot be used on CDMA networks. With the introduction of 
the iPhone 4, GSM and CDMA versions were made available. The iPhone 4S and later are "world phones," meaning that there is one version for both GSM and CDMA. However, the CDMA radio is disabled on GSM phones. Only phones sold on a CDMA carrier have the CDMA portion enabled, and again, can only be used on that particular CDMA carrier.

CDMA phones can only be used with the CDMA carrier that they were obtained from. Verizon phones come unlocked (though they still require a two-year contract if purchased at the subsidized price), meaning that they can be used with any GSM carrier, but not any CDMA carrier other than Verizon. Sprint reportedly will unlock iPhones after a contract for international use only.

iPads and 3G/4G
If you choose the cellular model of iPad, it comes unlocked and without a contract. The only exception is if you bought it from a carrier, as in some cases, they may discount the price of the iPad if you sign up for a contract. You only need to pay for data, and there is no texting or phone plan. If there is no contract, you can just pay by the month and stop service any time. You can still text using Apple's iMessage service on iOS 5 and later, but this is not done through the carrier. Another nice thing about a 3G/4G model is that it comes with a built-in GPS, making location data much more accurate, as opposed to a Wi-Fi only iPad or an iPod touch which gather location data using Wi-Fi, although Wi-Fi is more accurate than 3G/4G. You can enroll in a data plan on any supported carrier, and cancel it whenever you want. All iPads come unlocked; there is no higher price to get an unlocked model, it's just $529 for 16GB, and $100 more for each GB (gigabyte) size up.

Note that if using iMessage on 3G/4G, although it does not count towards a texting plan, it will still count towards your data plan. If using Wi-Fi
it will not count against your plan.

The iPad (3rd generation and later) Verizon/Sprint (CDMA) model also has a GSM radio in it, so it can work with both.

Activation Issues
If you get a "Could not activate" message on your phone, this could be for a couple of reasons. One is that there is no SIM card in the phone.
If you are trying to use the iPhone without service, as if it were an iPod touch, it still needs a SIM card in it at the initial point of activation. The
SIM does not have to be active, but you do need one in the phone. It can be removed once the phone is set up.  If the phone is locked to a carrier, a SIM card from that carrier needs to be used.

Another reason is if a user tried to bypass a carrier lock and unlock it by hacking. Such modifications are illegal (provided the phone's contract is still in effect) and unreliable, and this message is the result of that attempt.

Note that this is different from "Activation Lock," a feature of Find my iPhone in iOS 7 and later that prevents a phone from being set up without entering the Apple ID and password used to set up Find my iPhone on the phone.

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Comments (15):

By Sheila on 1/16/15 • Reply
Hi. I have an iphone 6 plus that is on 02 UK network. I'm from lreland. The phone has not been activated. Should I use a UK SIM card are an Irish SIM card?? The phone will also need to be unlocked so can I unlock it before it's activated? Thanks a million. 

in response to Sheila
By AppleClubSupport on 1/16/15 • Reply
Hi Sheila,
You will need to see if O2 will unlock the phone before you can use it on an Irish carrier's network. Once unlocked, it can be activated with any carrier's SIM card.

in response to AppleClubSupport
By Sheila on 1/16/15 • Reply
Ok 02 UK are 02 lreland? Thanks a mill

in response to Sheila
By AppleClubSupport on 1/16/15 • Reply
I wasn't aware that the UK carrier and the Irish carrier you were referring to were both O2.
In that case, you can probably just obtain a new SIM card , but you need to contact O2 for a definite answer.

in response to AppleClubSupport
By Sheila on 1/16/15 • Reply
The phone is locked to 02 UK so I would be guessing that 02 UK would be my best bet, I did actually contact 02 lreland and they told me to contact 02 UK. I'm confused be couse I was chating to a member of 02 lreland today and she said an 02 lreland sim would work and then I was told that I would need a UK sim so I'm very confused about the hole thing. Thanks so much for your help. 

By Zaide on 1/17/15 • Reply
Hi i have an Iphone 4s and it's GSM factory Unlocked,is that possible that i can use an AT&T microsim card or T-mobile? Or do i have another option?

in response to Zaide
By AppleClubSupport on 1/17/15 • Reply
Either AT&T or T-Mobile would work.

in response to AppleClubSupport
By Zaide on 1/17/15 • Reply
Thanks for your responce,.. I want to know one more thing,. Is that possible than i can have prepaid or plan? I would like to have prepaid u know,. Is that possible that i can have prepaid?

in response to Zaide
By AppleClubSupport on 1/17/15 • Reply
You'll need to ask the carrier you intend to use it on.

in response to AppleClubSupport
By Zaide on 1/22/15 • Reply
Hi,it's me again. I'm just a little confused,I was looking for a microsim card on ebay and I've seen these different at&t microsim cards, like H2o wireless at&t,straight talk microsim card for at&t,NEt10 at&t,and red pocket microsim card use for at&t, can I use any of those microsim cards for my Iphone?
My phone is Iphone 4s
Carrier: unlocked
GSM unlocked:not compatible with CDMA carriers

in response to Zaide
By AppleClubSupport on 1/23/15 • Reply
Yes, you can use the SIM card for any GSM carrier, and then sign up for service with that carrier.

By LoriV on 1/24/15 • Reply
So I am in the reprocess of getting my iPhone 4 unlocked through AT&T so I can sell it as I have upgraded and no longer need my 4. People are asking if they can connect it to any carrier. I have no idea, any input would be helpful. 

By Robin228 on 2/12/15 • Reply
Very clear and easy to understand. Thanks.

By ayeshamasood on 3/06/15 • Reply
I was wondering if I can get an unlocked iPhone from the U.S. and bring it to another country and get it unlocked somehow by a techie or something. Or even I don't get it unlocked and just use it for the internet and stuff with wifi so will that be illegal? Can the contract holders know this? Please answer me. The unlocked iPhone is toooo expensive.

in response to ayeshamasood
By AppleClubSupport on 3/06/15 • Reply
It is illegal to have a third party hack to unlock your phone while it is on contract. Third party unlocks are untrustworthy anyway.