An unlocked phone is a phone that isn't restricted to a single carrier's network, so it can accept a SIM or eSIM from any provider it's compatible with.
Phones bought through a carrier almost always arrive locked, because the carrier discounted the price through bill credits or an installment plan and wants the device on its network until that balance is settled. Once you meet your carrier's unlock requirements, the lock comes off, and nothing about the phone itself changes.
What is an unlocked phone?
An unlocked cell phone accepts service from any compatible carrier, not just the one that sold it. You can buy an unlocked smartphone straight from Apple, Samsung, or Google at full retail, or you can unlock a phone you already bought from your carrier once you've paid it off.
Keep in mind that an unlocked phone costs full retail price—rather than the discounted price a carrier gives you for staying on its network. However, an unlocked phone resells for more than a locked one since the next owner can take it to any carrier.
What's the difference between a locked and unlocked phone?
A locked phone only works on the carrier that sold it, while an unlocked phone works on any carrier you want to use. Putting another carrier's SIM in a locked phone usually returns a "SIM not supported" error instead of connecting to the new network.
A locked phone doesn't stay locked forever, and your carrier will remove the lock once you meet its requirements. Every carrier sets its own unlocking requirements, but most come down to paying off the phone, keeping your bill current, and waiting out a minimum service period.
Will an unlocked phone work with any carrier?
An unlocked phone works with nearly every US carrier since almost every newer phone uses the same frequencies as any of the major networks. Older phones and phones bought in another country are the exceptions, since a device bought overseas comes with no guarantee it will work the same way one bought here does. If you bought your phone overseas or it's several years old, check it with the new carrier's phone compatibility tool before switching.
How to tell if your phone is already unlocked
You can tell whether your phone is unlocked by checking your device settings, under Carrier Lock on iPhone and Network operators on Android:
- iPhone: Settings > General > About > Carrier Lock, which reads "No SIM restrictions" when the phone is unlocked
- Android: Settings > Connections > Mobile networks > Network operators > Search now, and several available networks generally means the phone is unlocked
Tap Connections in your Settings menu, then select Mobile networks on a Galaxy Z Fold5.
Image: Scott Houghton | WhistleOut
You can also confirm whether your phone is unlocked by inserting another carrier's SIM card. An unlocked phone will connect to the other carrier, and a locked phone won't.
What can you do with an unlocked phone?
An unlocked phone can move to any carrier, including prepaid brands, or use a local SIM while you're traveling, all without any hardware upgrades. Switching carriers is where you save real money, since an unlocked phone lets you compare what every carrier charges instead of staying with the one that sold you the device.
Smaller carriers like Mint Mobile, US Mobile, Visible, and Cricket Wireless run on the same networks as the big three and typically charge less for comparable service.
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Mint Mobile
Unlimited Data Plan
$15.00/mo
$45 for 3 months of service
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Visible
$19 Visible Plan
$19.00/mo
Taxes & Fees included
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US Mobile
Unlimited Starter Plan
$25.00/mo
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Cricket
Supreme Unlimited Plan
$55.00/mo
with AutoPay; $60 for the first month.
+ $9.99 Upfront
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Unlocked phones: FAQ
Are prepaid phones unlocked?
Prepaid phones bought from a carrier are locked, and prepaid unlock windows typically run longer than postpaid ones, often six months to a full year of paid active service. Our guide to unlocking a prepaid phone breaks down what each prepaid brand requires.
Does unlocking a phone cost anything?
Unlocking is free for current customers in good standing at every major US carrier. Any service charging you to unlock a phone you already own and have paid off is selling you something your carrier will do at no cost.
Can I unlock a phone I'm still making payments on?
Most carriers won't unlock a phone still carrying an installment balance since every major carrier treats a paid-off device as the baseline requirement. Paying off the remaining balance early usually makes the phone eligible to unlock right away. For prepaid brands, they often require a minimum length of service no matter what the device balance says.
Does unlocking a phone erase my data?
Unlocking a phone doesn't erase photos, apps, messages, or settings, because the carrier lock lives in the phone's software rather than in your storage. Switching carriers afterward is a separate step, and that's when you may need to update your APN settings or re-register features like Wi-Fi calling.
Do unlocked phones work internationally?
An unlocked phone can use a local SIM or travel eSIM abroad, which is usually far cheaper than paying your home carrier's international day pass. Coverage still depends on the network bands your specific model supports, so check the phone's supported bands against the local network before the trip.
Scott Houghton
Jr. Staff Writer
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