Buying a secondhand phone is one of the smartest ways to get a quality device for less money. But the used phone market also has a dark side: stolen devices sold by people who know exactly what they are doing, and buyers who have no idea until it is too late.
This guide explains how to check if a phone is stolen before you buy — and what it means if the check reveals something concerning.
Why Stolen Phones End Up on the Used Market
Stolen phones are valuable. A flagship iPhone or Galaxy S series phone can sell for several hundred pounds or dollars on the secondhand market, and sellers often rely on buyers not knowing to check the device's history.
The most common routes for stolen devices to reach buyers include:
- Social media marketplaces (Facebook Marketplace, Gumtree, Craigslist)
- Auction sites (eBay listings from accounts with no selling history)
- Cash-in-hand local deals where there is no paper trail
- Import dealers who may not know the device's origin
Legitimate sellers have nothing to hide and welcome verification checks. Reluctance to share an IMEI is itself a warning sign.
The Core Method: IMEI Blacklist Check
Every mobile device has an IMEI (International Mobile Equipment Identity) — a unique 15-digit number that identifies the hardware. When a phone is reported stolen, the owner or carrier can add this IMEI to a global blacklist database maintained by the GSMA. Carriers worldwide use this database to block blacklisted devices from connecting to their networks.
Checking the IMEI against this blacklist is the most reliable way to identify a stolen phone.
How to get the IMEI before buying:
- Ask the seller to dial
*#06#and show you the IMEI displayed on screen - Cross-reference it with the IMEI shown on the original box (if available)
- If buying remotely, ask the seller to photograph the IMEI screen — but verify in person if possible
Running the check: Enter the IMEI into DeviceDecoded's Lost & Stolen Device Database check. A clean result means the IMEI has not been reported to the databases we search. A blacklisted result means the device has been reported — walk away.
What Blacklist Status Means
Clean: The IMEI has not been reported to the blacklist databases we check. This is a necessary — but not sufficient — condition for a safe purchase. A device can be stolen and not yet reported.
Blacklisted: The IMEI is in one or more blacklist databases. Do not buy this device. It will lose cellular connectivity as soon as it connects to a network that checks the blacklist.
Reported: Some databases allow direct reporting of stolen devices outside of carrier channels. A reported flag may precede a formal blacklist entry and should be treated with equal caution.
Additional Checks Beyond the Blacklist
A clean blacklist result is reassuring but not a complete safety check. Layer it with these additional steps:
iCloud Activation Lock (iPhone and iPad) Ask the seller to go to Settings > General to show that Find My is disabled, and confirm the device is not linked to an Apple ID. Our iCloud Lock Check verifies this. A device with active iCloud lock cannot be set up without the previous owner's Apple ID.
Google Account / FRP (Android) Ask the seller to sign out of their Google Account on the device. After signing out, attempt a factory reset — if the device asks for the previous account credentials on next setup, Factory Reset Protection is active and the device should not be purchased without resolving this.
Samsung Knox Guard For Samsung Galaxy devices specifically, run a Samsung Knox Check. Knox Guard allows carriers to remotely lock financed devices — a Galaxy with active Knox Guard can be blocked at any time.
Ask for proof of purchase A legitimate seller can provide a receipt, invoice, or carrier purchase confirmation. No receipt does not mean the phone is stolen, but the combination of no receipt + no original box + reluctance to share IMEI is a strong red flag.
Buying in Person: The On-the-Spot Check
When meeting a seller in person, the most powerful check is watching them reset the device in front of you:
- Have the seller sign out of iCloud (iPhone) or Google Account (Android) on the device
- Then Factory Reset the device through settings
- Watch the device start fresh — it should not ask for a previous account password
- Only then hand over payment
This is the gold standard check. Any seller who refuses to do this before accepting payment should be treated with extreme caution.
Red Flags That Suggest a Stolen Phone
- Seller cannot provide original box or proof of purchase
- Price is dramatically below market value for the model
- Seller is insistent on cash only with no receipt
- IMEI on device does not match IMEI on box
- iCloud or Google account is still active and seller "doesn't know the password"
- Device has been reset but asks for an account on first setup
- Seller becomes evasive when asked about IMEI check
What If You've Already Bought a Stolen Phone?
If you discover after purchase that a device is blacklisted or stolen:
- Do not use the device — this could be construed as receiving stolen goods
- Contact police with your purchase evidence
- Report to the platform where you bought it and file a buyer protection claim
- Contact the carrier identified in the IMEI check — they may have more information
The best protection is verification before purchase. DeviceDecoded's IMEI Check takes seconds and is free for one check per day without registration.