What "carrier-locked" means
A carrier-locked phone will only accept a SIM card from the one network it was sold with (or that network's family of brands). Insert a SIM from a different carrier and the phone will refuse to make calls, send texts, or use mobile data — usually with a message like "SIM not supported" or "invalid SIM".
Carriers do this because many phones are sold at a discount tied to a contract or an installment plan. The lock is the carrier's guarantee that the phone stays on their network until that commitment is honoured. It's a restriction on the hardware, not a statement about who owns the phone — you own it either way, locked or not.
What "unlocked" means
An unlocked phone accepts a SIM from any compatible carrier, anywhere. It might have started life locked and been unlocked later — through the original carrier, or a service like ours — or it might have been sold unlocked from day one, which is how many phones bought directly from a manufacturer are sold.
Neither state says anything about who owns the phone, whether it was expensive, or how new it is. A brand-new flagship can be locked, and a years-old budget phone can be fully unlocked — the two things are unrelated.
How to tell which one yours is
- iPhone: Settings → General → About → Carrier Lock. "No SIM restrictions" means unlocked; anything else names the lock.
- Android: Settings → Network & internet (or Connections) → look for a SIM lock or network lock status; wording varies by manufacturer.
- The universal test: borrow a SIM from a friend on a different network. If it connects, you're unlocked.
One nuance worth knowing: prepaid phones are sometimes locked under slightly different rules than postpaid, financed phones, since there's no installment balance to protect — but many prepaid carriers still apply a short lock period to discourage bulk resale of subsidized devices. The Settings check and the borrowed-SIM test above work the same way regardless of which kind of plan the phone came from.
What actually changes once you unlock
| Carrier-locked | Unlocked | |
|---|---|---|
| Works with your current SIM | Yes | Yes |
| Works with another carrier's SIM | No | Yes |
| Works with a local SIM abroad | No | Yes |
| Typical resale value | Lower — smaller buyer pool | Higher — see the benefits guide |
Unlocked doesn't mean carrier-free
It's a common mix-up: unlocking a phone doesn't disconnect it from cellular networks altogether, and it doesn't mean you no longer need a SIM or a plan. It simply means the phone stops refusing to work with other carriers' SIMs. You'll still insert a SIM and still need service from some carrier — you've just stopped being restricted to one specific choice.
Why carriers lock phones at all
The economics are straightforward: a carrier that sells a phone at a discount, or lets you pay it off over time, wants some guarantee it keeps earning your service revenue until that cost is recovered. The lock is that guarantee. It's also why the lock is tied to the phone paying off its balance and staying in good standing — see is my phone eligible for unlock for exactly what that involves.
For the full list of what improves — resale value, travel, switching freedom — see the benefits of unlocking your phone. For how the unlock itself is carried out, see how carrier unlocking works.
Does unlocking cost me anything on my current plan?
No. Unlocking only removes the restriction on which SIMs the phone accepts — it changes nothing about your existing plan, number, or contract with your current carrier.
Can a locked phone still be checked for blacklist status?
Yes — a blacklist and a carrier lock are independent checks. Run both from the IMEI check page before you rely on a phone.
If I buy a phone directly from a manufacturer, is it always unlocked?
Usually, yes — phones bought unbundled from a contract are typically sold unlocked, but it only takes a minute to confirm with the Settings check above rather than assume.
Is an unlocked phone the same thing as a "factory unlocked" phone?
Effectively yes for day-to-day use — "factory unlocked" just specifies it was never locked in the first place, rather than unlocked afterward. Both end up in the same unlocked state.
Enter your IMEI and current network to see your price.
