Happy with your iPhone, but think you're paying too much for data and text? We've all been there, to be honest. Sometimes swapping mobile carriers is a good idea, but there can be a slight problem: if your iPhone is locked to a particular network, it will need to be unlocked before accepting another carrier's SIM card.
If that sounds complicated, don't worry. We've gone over all the information you need to understand Operator Unlocks below. Remember that a media lock is different from a screen lock. The latter prevents you from accessing a phone while the carrier lock prevents you from using another network provider (if you have Verizon, you cannot use AT&T until the device is unlocked by the operator).
How to know if your iPhone is locked
There are several ways to tell if your iPhone is unlocked. Let's review the methods.
Use a SIM card
Not sure if your phone is locked? Well, this piece is quite easy. Just take out your existing SIM card and try a new one from another operator. If you bought your iPhone directly from an Apple Store, it will be unlocked by default, so swapping between SIM cards from different networks is quick and easy – and you shouldn't even need to restart your phone.
If however, your iPhone is locked, you will get error messages such as "Invalid SIM" or "No SIM Card Installed". It might not mean your phone is locked — it might just be an iOS crisis. If you're in this bracket, it's just a matter of toggling Airplane mode on and off and restarting the phone — or reinstalling the SIM card.
Otherwise, go to Settings | General | About and tap "Check for carrier settings update".

Notes: It is best to use a T-Mobile or AT&T SIM card if possible (on the GSM network). Some CDMA phones require very specific SIM cards which vary between phone models. This means that your phone may be unlocked but it does not recognize the SIM card you have inserted.
Check with the carrier
Most carriers have the ability to check if your phone is ready to be activated on their network. AT&T for example has this website. You can enter your phone's IMEI number and get an alert if it's ready to be activated or if it's still locked in a previous carrier.

If you receive the message "SIM locked", you are out of luck and will need to find a way to unlock your phone.
Find out if a phone is unlocked before buying
A common problem with phones that are not unlocked is when they are sold to another person. If you buy a locked phone from the original purchaser, you will be at their mercy to unlock it. Of course, you can check with your carrier to see if the IMEI is compatible, but that won't always tell you if the phone is unlocked.
Your best bet is to meet the seller at your carrier's store and activate service over the phone before paying (most honest sellers will do this). But if you're buying the phone on eBay or having it shipped to you, that's not an option.
Your next option is to use a third-party website to run the IMEI for you. But, as always, there are risks with this too. Most of these sites charge fees and some are not even accurate. If you go to the original carrier's website, you might be lucky, but you'll need the original account number and other key information that the seller might not want to give you. .
What do I need to unlock my iPhone?
If you purchased your phone as part of a contract, your phone will only be locked to their network until the terms of the contract, lease, or down payment are met.
If you bought your phone second-hand, it's a little trickier: if you can't convince the seller to unlock it for you, you may need to go through a few steps.
If the phone was originally purchased as part of a contract or lease, you will likely need the original account holder information to unlock the phone. Otherwise, this phone will be stuck with this carrier forever.

How to unlock your iPhone
If your phone was purchased on a postpaid account on one of the four major carriers in the United States, you will need to go through that carrier to get the phone unlocked. Each carrier has their own process and criteria for releasing the phone.
AT&T
AT&T devices must be active on the network for at least 60 days before the company will unlock them for you. AT&T's unlock policy, assuming you meet the requirements, is one of the easiest and easiest options.

To unlock your phone, AT&T makes it easy. Visit their website for device unlock and enter your account/device information. You will receive a terms and conditions email once you submit the request.
Check your email and follow the steps to confirm that you want to unlock your device. Once done, you will receive an email stating that your device is unlocked within 24-72 hours.
T Mobile
Your iPhone must be free of any covenants or contractual obligations and must have been active on the T-Mobile network for at least 40 days to be eligible.
Visit your T-Mobile Online Account and navigate to the phone you want to unlock under "View Account", then "Lines & Devices". Submit the request to unlock this device and wait for the confirmation email.

Once the request is approved (approximately 48 hours), your phone is automatically unlocked for use on another carrier's network.
Verizon
Verizon has one of the friendliest unlocking policies for consumers, as it will automatically unlock a device sixty days after purchase. If you're having trouble with this, you'll need to contact the Verizon customer support team to unlock your iPhone.

The confusion of unlocking the iPhone 5 aside, the company has maintained a fairly straightforward policy on unlocking the devices. Depending on how old your iPhone is, it's probably already unlocked.
Sprint
Sprint will automatically unlock a device once the conditions are met as long as it is able to unlock the SIM card. Unfortunately, devices manufactured before 2015 and unable to be unlocked for home use (you can take it abroad after contacting customer support). The company will provide an MSL code for these devices, but iPhones do not use MSL (Master Subsidy Lock) codes so it's useless.
The company's basis for this is that iPhones made before 2015 were not required by law to be carrier unlocked, so the company never gave its customers the option. If you're using an iPhone 6 or older, it's unlikely your phone will ever be unlocked from Sprint's network.

If you need to unlock your device to travel abroad, or if your device does not unlock automatically, you can contact Sprint Customer Service.
To note - This information is subject to change as T-Mobile and Sprint have just completed their merger. Although the official word in May 2022 is that the unlock policy will remain the same, you can check out the latest information regarding Sprint's device unlock policy. here.
Final steps
Now that the carrier has (hopefully) unlocked your phone; insert the new operator's SIM card into your phone. If you don't have a new SIM card yet (like if you're waiting to travel), back up your iPhone, reset it, then restore it with all your data.
Doing a reset will ensure it's unlocked and ready for international travel. Before you go, try using another friend or family member's SIM card (preferably AT&T or T-Mobile) in your phone to make sure it will work on the GSM network.
Frequently Asked Questions
Here are some additional answers to help you better understand iPhone unlocking protocols and policies.
Can I use a third party site to unlock my device?
There are many websites that promise to unlock your iPhone, especially older models like the ones mentioned in this article. Unfortunately, it is unlikely that any of these websites will have access to the information needed to perform a successful unlock.
Most of these sites ask for payment information and device information to be used maliciously. It is best to contact the carrier directly.
I want to buy a phone from Facebook Marketplace, how can I be sure it's unlocked?
If you buy a phone from an individual or a third-party seller, you can find the IMEI number on your carrier's website. If it says it's available for activation, you're good to go.
The best option for anyone buying a new phone is to meet the salesperson at your carrier's store. This will ensure that the phone is activated and there is no damage. An older iPhone will likely no longer come with AppleCare, so it's ideal to have trained staff to help you make the purchase.
Do I need an unlocked phone to travel abroad?
No, but it's best to have an unlocked phone for international travel. The iPhone 5-7 is a perfect travel phone. When you reach your destination, start a prepaid service with a company from that country to avoid having to pay expensive international roaming charges.
What if I am deployed in the military?
Most carriers will put your phone number on what's called a "military suspension." This means your monthly charges will be suspended while employed and your phone can be unlocked for international travel.
Check with your carrier prior to deployment to review your options.
My iPhone is unlocked but it is blacklisted. What does this mean and how do I fix it?
Blacklisting is totally different from carrier locks. When a device is blacklisted, it means that it cannot be activated on any operator. Most often, this means that your phone has been reported stolen.
If you didn't originally buy the phone, there really isn't much you can do to activate it. Even calling the original carrier who blacklisted the device probably won't help, as it will appear to be someone else's stolen property.
If you originally purchased the iPhone and it is blacklisted, contact the carrier you purchased it from to find out what can be done. Based on experience, this can be a long process that needs to be stepped up several times. The blacklist is meant to be a permanent block, so be prepared to spend some time on it.
My phone is unlocked but my current carrier says it is not compatible, how is this possible?
Some older iPhone models were not compatible with different carriers. For example, AT&T's iPhone X was not compatible with the Verizon network. So, even if you have an unlocked iPhone, make sure that the carrier you want to activate it on is compatible with the model number you have.
The model number is listed on the back of your iPhone and looks like a combination of letters and numbers (for example, "A1660" indicates some iPhone 7 models).