How to Check if Your iPhone Is Unlocked (Carrier Lock Explained)

A carrier-locked iPhone only works with SIMs from one carrier. That matters when you want to switch networks, use a local SIM abroad, or buy or sell a second-hand phone. Checking takes ten seconds.

I build Secret Codes: IMEI & Carrier, a free iPhone app with 317 verified dial codes, and the screenshots in this guide come from it. If you would rather tap than memorise codes, get Secret Codes on the App Store.

How do I check if my iPhone is unlocked?

1. Open Settings.
2. Go to General > About.
3. Scroll to Carrier Lock.

• "No SIM restrictions" means the iPhone is unlocked.
• "SIM locked" or a carrier-specific message means it is locked to a carrier.

This row is shown on recent versions of iOS. On a very old iOS version, the reliable test is to try a SIM from a different carrier.

What is the difference between carrier lock and activation lock?

	Carrier lock	Activation Lock
What it does	Restricts which carrier's SIMs work	Ties the iPhone to the owner's Apple Account
Who controls it	The carrier	The owner, through Find My
How it is removed	The carrier unlocks it	The owner signs out or removes the device from their account

A second-hand iPhone can have either, both or neither. Activation Lock is the more serious problem: a phone with it on cannot be used by anyone else.

How do I unlock a carrier-locked iPhone?

Only the carrier that locked it can unlock it. Each carrier has its own policy, often requiring that the phone is fully paid off and has been active on the account for a minimum time. To request an unlock:

1. Find your IMEI by dialling *#06# (see how to check your IMEI).
2. Contact the carrier or use its online unlock request form.
3. Once approved, the unlock is applied on the carrier's systems. You may need to insert a new SIM, or back up and restore the iPhone, to complete it.

What should I check when buying a used iPhone?

• Carrier Lock says "No SIM restrictions", or is locked to the carrier you use.
• Activation Lock is off: the seller should sign out of their Apple Account and erase the phone in front of you.
• The IMEI is not reported lost or stolen. Many carriers and countries provide IMEI check services.
• The IMEI in Settings matches the one on the box, if there is one.
• Battery health in Settings > Battery.

Secret Codes' diagnostic suite can also test the display, touch, cameras, speaker, microphone, sensors and Face ID before you hand over money.

More guides you may find useful:

• iPhone Field Test Mode (*3001#12345#*): How to Check Your Real Signal Strength
• Android Secret Codes on iPhone: *#*#4636#*#*, *#0*# and What to Use Instead
• What Does ##002# Do on iPhone? Cancel All Call Forwarding (and Keep Your Voicemail)

How Secret Codes helps

• 317 verified iPhone codes, each checked against a carrier, Apple or the 3GPP standard. Android-only and retired codes are left out.
• Plain-English explanations of what every code does before you dial it.
• Open in Phone puts the code in Apple's dialler. Nothing is ever dialled for you.
• Built around your carrier: each code says whether your network publishes it.
• A full diagnostic suite for battery, storage, Wi-Fi, cellular, display, touch, cameras, sensors and Face ID.
• IMEI in one tap with Siri, Spotlight, Shortcuts and a Home Screen quick action.
• Free, with nothing locked: no paid tier and no subscription.

Download Secret Codes free on the App Store and keep every working iPhone code in your pocket.