How to Check a Phone's IMEI Before You Buy Secondhand in NZ
If you're buying a secondhand or refurbished phone in New Zealand, there's one five-minute check that can save you from a very expensive mistake: looking up the IMEI. It won't tell you everything about a phone's history, but it will catch the two things that matter most — whether the phone is reported lost or stolen, and whether it's still tied to a finance or carrier contract somewhere.
What an IMEI actually is
Every phone has a unique 15-digit IMEI (International Mobile Equipment Identity) number, a bit like a chassis number for a car. It's stamped into the phone's hardware, so unlike a serial number on a box, it can't be swapped out. You'll find it by dialling *#06# on the phone itself, or under Settings > General > About on iPhone, and Settings > About Phone on Android.
Why it matters more for secondhand buying
When a phone is reported lost or stolen, the owner or their insurer can have the IMEI blacklisted with the carriers. A blacklisted phone might power on fine and even connect to Wi-Fi, but it will refuse to register on any mobile network — here or overseas. You won't discover this until after you've paid and tried to put a SIM in it, and by then a private-sale seller is usually long gone.
It also flags devices still owed on finance through a carrier or a buy-now-pay-later phone plan. These sometimes get sold on before the debt is cleared, and while that's not your fault as a buyer, it can still mean the phone gets remotely locked or blacklisted later once the original owner falls behind on payments.
How to actually check it
You've got a few options, roughly in order of convenience:
1. Ask the seller to run it themselves. If you're buying from a private listing (Trade Me, Facebook Marketplace), ask the seller to send you a screenshot from a free IMEI checker before you commit. A seller who refuses or gets cagey about this is a red flag on its own.
2. Use a free checker once you have the phone in hand. Sites like imeicheck.net or swappa.com/imei offer basic blacklist and carrier lock checks for free — enough to confirm the phone isn't reported lost, stolen, or blacklisted. Paid checkers (a few dollars) add more detail, like carrier network history and whether Find My iPhone / Activation Lock is still active.
3. Check Activation Lock and FRP separately. IMEI blacklist status is different from Apple's Activation Lock or Android's Factory Reset Protection (FRP), both of which can leave a phone essentially unusable even if the IMEI is clean. Always insist on watching the seller fully sign out of their Apple ID or Google account, and do a factory reset yourself, before handing over money.
Where refurbished retailers fit in
This is exactly the checking that a proper refurbished retailer should have already done before a phone ever gets listed. At SmartGear NZ, every device is IMEI-checked, wiped of the previous owner's account, and factory reset as part of grading, before it goes up for sale — so an iPhone SE or an Galaxy S23 FE from our shelves arrives clean, unlocked from any prior account, and ready to activate on any NZ network straight away.
That's really the trade-off between buying from a private listing and buying from a graded refurbished seller: private sales can be cheaper, but the IMEI and account checks are entirely on you. Buying from a retailer who does that checking as standard removes the guesswork, along with giving you a warranty if something turns up faulty later.
The five-minute checklist
Before you hand over money for any secondhand phone, run through this: IMEI comes back clean on a blacklist checker, seller signs out of their Apple ID / Google account in front of you, factory reset completes without asking for a previous owner's password, and the phone successfully registers on a SIM (yours or a shop demo SIM) before you leave. If any one of those fails, walk away — no discount is worth the risk of ending up with a phone you can't actually use.