You're standing on a street corner or sitting in a coffee shop, staring at a "mint condition" iPhone 15 Pro Max. The price is a steal. Maybe too good. You've got the cash in your pocket, but one nagging thought keeps you from handing it over: Is this thing actually going to work with my SIM card? If you're looking for how to check if an iPhone is unlocked with IMEI, you're probably trying to avoid buying a very expensive paperweight. It happens way more than it should.
People get burned constantly because they take a seller's word for it. Don't do that.
IMEI stands for International Mobile Equipment Identity. It’s a 15-digit fingerprint for every single phone on the planet. Honestly, it’s the most powerful tool you have when buying a used device. It tells the story of where the phone has been, who it belongs to, and whether or not it's "shackled" to a specific carrier like AT&T or Verizon.
Finding the Magic Number
Before we get into the checks, you need the number. It's easy. Just open the Phone app and dial *#06#. Boom. A screen pops up with your IMEI. If the phone is wiped and sitting on the "Hello" screen, just tap the small "i" icon in the bottom right corner. It’ll show up there too.
You can also find it in Settings > General > About. Scroll down. It’s near the bottom. Sometimes it’s even printed on the SIM tray, but that’s less reliable because trays can be swapped between phones easily. Stick to the software.
How to check if an iPhone is unlocked with IMEI using online tools
There are a million websites claiming they can do this for free. Most are garbage. They’re usually just trying to sell you a "premium" report or they're harvesting your data to spam you later. However, a few are actually legit and provide the basic "Locked/Unlocked" status without asking for a credit card.
Sites like IMEI.info or SickW have been around forever. You punch in the 15 digits, solve a CAPTCHA, and wait. Sometimes the result says "Carrier: Locked" or "Carrier: Open." If it says "Multi-mode" or "Unlocked," you’re usually golden. But here’s the kicker: these databases aren't always 100% up to date. They rely on "scraping" data from carrier servers.
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If the phone was unlocked yesterday, the website might not know it yet.
A much more reliable way is to use an "IMEI Checker" that specifically looks for GSMA blacklists. If a phone is reported stolen, it doesn't matter if it's "unlocked"—it won't work on any major network in the US. CTIA’s Stolen Phone Checker is the gold standard for this. It’s a non-profit tool used by the industry. It won't tell you the lock status directly, but it tells you if the phone is a "brick" in the eyes of the law.
The "Setting" trick (No IMEI needed)
Wait. There’s actually a way to see the lock status directly in the iPhone settings without even using the IMEI on a website. It’s sort of a "hidden in plain sight" feature Apple added in iOS 14.
Go to Settings.
Tap General.
Tap About.
Look for a field called Carrier Lock.
If it says "No SIM restrictions," the phone is unlocked. Period. If it says "SIM Locked," you’re stuck with whatever carrier is listed there until it’s paid off or the contract is finished. This is way faster than using a website, but it requires you to have the phone in your hand and have it past the activation screen.
Why the IMEI check matters for your wallet
Carriers use locks to ensure you pay off your phone. If you buy a "locked" phone, you are essentially inheriting someone else's debt. If they stop paying their bill, the carrier will blacklist that IMEI. Suddenly, your phone loses its ability to make calls or use data.
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I’ve seen people buy iPhones on Facebook Marketplace that worked fine for two weeks. Then, one morning, "No Service." The original owner stopped making payments or filed an insurance claim for a "lost" phone. The IMEI got flagged. Game over.
Checking the IMEI allows you to see the "Financial Eligibility" of the device. Swappa has a great free tool for this. It checks if the device is currently under a finance plan. If it is, walk away. Or, at the very least, make the seller pay it off in front of you.
Misconceptions about "Unlocking"
A lot of people think an "unlocked" phone is somehow "jailbroken" or modified. It's not. It just means the software policy on Apple's servers says "This device can accept any SIM."
There are "factory unlocked" phones, which were bought straight from Apple. These are the best. They have never been tied to a carrier. Then there are "carrier unlocked" phones. These were originally sold by someone like T-Mobile, but the owner met the requirements (usually 40-60 days of service and a fully paid-off device) and requested an unlock.
Both are functionally the same, but a factory unlocked model often has better resale value.
The technical hurdle: CDMA vs. GSM
This is a bit old-school, but it still matters for older iPhones. Before the iPhone 12, there were different hardware versions for different carriers. Some only worked on GSM (AT&T/T-Mobile) and others worked on both GSM and CDMA (Verizon/Sprint).
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If you check the IMEI on a site like EveryMac, you can see the specific model number (like A1660). This tells you if the hardware even supports the bands of the carrier you want to use. Since the iPhone 13 and 14, Apple has mostly unified the hardware, so this is less of a headache than it used to be, but it’s still worth checking if you’re buying an older "legacy" device for a kid or as a backup.
What to do if the IMEI says "Locked"
So you checked. It’s locked. Now what?
You can’t just "hack" an IMEI unlock anymore. Those R-SIM or GPP "interposer" stickers you see on eBay? They are a nightmare. They trick the phone for a while, but as soon as you update iOS, they break. They also drain your battery because they are constantly "faking" the handshake between the SIM and the modem.
The only real way to unlock it is through the carrier. If the phone is clean and paid off, the original carrier is legally required to unlock it for you (in many jurisdictions).
- AT&T has a specific portal where you can enter the IMEI and request an unlock as a "non-customer."
- T-Mobile usually requires the account holder to make the request.
- Verizon automatically unlocks most phones after 60 days of activation.
If the carrier says no because of an unpaid balance, you’re basically out of luck unless you want to pay off someone else's bill. This is why the IMEI check is your shield.
Actionable Next Steps
If you are about to buy a phone, do exactly this:
- Get the IMEI. Don't let the seller send you a screenshot. Get it from the device yourself.
- Check Settings > General > About. Look for "No SIM restrictions." This is your first and best line of defense.
- Run the number through Swappa's IMEI checker. It’s free and checks for both the blacklist and outstanding financial "holds."
- Use the CTIA Stolen Phone Checker. This ensures the phone isn't currently reported as lost or stolen by a major carrier.
- Test a SIM. If the seller is legit, they’ll let you pop your own SIM card in. If it gets a signal and shows your carrier’s name in the top corner, it’s unlocked.
Buying used is a great way to save five hundred bucks, but only if you do the legwork. A 30-second IMEI check can be the difference between a great deal and a total loss. Check the number. Every time. No exceptions.