How to tell if a phone is carrier-locked before you buy

1 day ago
3 min read

Myth: A phone that powers on is unlocked

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Many buyers assume that if a phone boots and shows signal bars it must be unlocked. **That is not true.** A locked phone can still work with the original carrier and show full service. Don't judge unlock status by power or bars.

Reality: You need tests that look beyond power and signal

When you test a device, **inspect the SIM tray and current SIM usage**. A locked phone will accept a SIM from the original carrier and show service. To be sure, try a SIM from a different carrier (prepaid or a friend) and watch for an error like "SIM not supported" or prompts to enter an unlock code. If the phone accepts a different carrier SIM and makes calls or uses data, it is likely unlocked.

Myth: If the seller says it's unlocked, you can trust them

Many people take a seller's word at face value. **Sellers often mean the phone works on their plan, not that it is carrier-unlocked.** Claims alone are not proof.

Reality: Ask for proof and check the settings

Request to see the phone's settings page that shows carrier details. On many phones an **IMEI status or "Network" field will say "Unlocked"**. Also, ask for the original receipt or carrier unlock confirmation message. If the seller refuses a quick SIM swap test, treat that as a red flag.

Myth: An unlocked-looking box or sticker means the phone is free to use

Boxes and stickers can be misleading. Retail packaging or a note on the case saying "Unlocked" does not guarantee network freedom. **Labels are easy to apply and hard to verify.**

Reality: Use the IMEI for a solid check

The IMEI (a long device number) is your best non-invasive tool. Ask the seller for the IMEI and check it with an online IMEI checker or the carrier. A check can show **carrier lock status, blacklist status, and model details**. If the seller won't share the IMEI, you should be cautious. Remember to do the IMEI check before you hand over cash.

Myth: If activation worked once on your SIM, the phone is unlocked forever

Some phones are unlocked temporarily, or need an activation step from the original carrier. **Activation success once does not guarantee permanent unlock.** Software updates or carrier policies can re-lock or restrict a device later.

Reality: Confirm permanent unlock with the carrier or written proof

Ask for written proof of unlock from the carrier or a screenshot of the carrier's confirmation. If the device was unlocked by the carrier, that record will show the date and status. **Carrier confirmation is the clearest proof** you can get before buying.

Myth: A factory reset will remove carrier locks

A reset clears personal data but does not remove a carrier lock. **Carrier locks are tied to the device firmware or IMEI record, not the stored contacts.**

Reality: Test after a reset if the seller insists on wiping the phone

If the seller wants to reset before you test, ask them to reset it in front of you and then repeat the SIM swap test. If a phone still accepts a different carrier SIM and connects, **that is a good sign**, but remember to confirm with the IMEI or carrier if possible.

Micro-moment

You meet a seller in a mall parking lot. They hand you a phone that looks clean. You pop in your prepaid SIM and the phone shows signal right away. You feel relieved. Then you ask to try a second carrier SIM. The seller hesitates and changes the subject. That pause tells you to walk away.

Fast check before you pay

Ask the seller for the IMEI and run an IMEI status check before handing over cash
Do a SIM swap with a different carrier SIM and try calling or using mobile data
Ask to see carrier unlock confirmation or a message from the carrier showing permanent unlock
Watch for seller hesitation to let you test with your own SIMs or to share the IMEI
Check for signs the phone was reported lost or stolen via the IMEI report
If possible, test after a factory reset done in front of you to ensure the unlock persists
Get any unlock promise in writing (text or photo) that you keep with the receipt