What Is a Carrier-Unlocked Phone? (And the 4 Other Locks That Can Still Block Your eSIM)

Quick answer: A carrier-unlocked phone is a phone that isn’t restricted to the network that sold it. It accepts a SIM or eSIM from any compatible provider, at home or overseas. To check an iPhone, go to Settings > General > About. If Carrier Lock says “No SIM restrictions”, it’s unlocked.

Key takeaways

• A carrier lock is a software restriction linked to your phone’s IMEI. Only the carrier that applied it can remove it.
• “Unlocked” doesn’t guarantee a travel eSIM will work. Four other issues can still stop it.
• In Australia, most postpaid phones are sold unlocked, but prepaid handsets often aren’t.
• Check your lock status at least 14 days before you fly. Some unlocks take a week or more.

What does “carrier-unlocked” actually mean?

When a carrier sells you a phone, it can add a software restriction called a carrier lock. You’ll also see it called a SIM lock or network lock. The phone checks every SIM or eSIM you add. If it isn’t from the approved network, the phone won’t connect.

Why do carriers lock phones? Mostly to protect the discount or instalment deal they gave you. They also argue that locks deter fraud. Verizon made exactly that case to the US regulator in 2025, saying subsidised phones were being trafficked overseas.

A carrier-unlocked phone has no such restriction. Either it was never locked, or the carrier removed the lock once you met its conditions.

Here’s a detail most guides skip. A lock usually ties your phone to a network, not a brand. A phone locked to Optus may accept a SIM from a smaller provider that runs on the Optus network. But it will reject a travel eSIM that connects to a foreign carrier. That’s the exact one you need overseas.

The terms you’ll see on listings

Term	What it means	Watch out for
Carrier-unlocked	Was locked, then released by the carrier	Confirm it in Settings, not just the listing
Factory-unlocked	Sold with no carrier lock from day one	Can still be a regional model with no eSIM
SIM-free	Bought outright, not tied to a plan	Telco prepaid phones bought outright may still be locked
Network-locked / SIM-locked	Only works with one network’s SIMs and eSIMs	Common on cheap prepaid handsets
“Unlocked” (marketplace)	A seller’s claim	Ask for the IMEI and a Settings screenshot

Locked vs unlocked phone: what changes for you

	Locked phone	Unlocked phone
Switching providers at home	Unlock first	Swap your SIM or eSIM any time
Travel eSIM or local SIM abroad	Usually fails to connect	Works if the phone supports eSIM and local bands
Upfront price	Often discounted or on instalments	Full retail price
Resale value	Lower, with fewer buyers	Higher, as any buyer can use it
Pre-installed apps	May include carrier apps	Usually cleaner

The trade-off is simple. A locked phone can be cheaper today. An unlocked phone becomes cheaper the moment you travel, switch plans or sell it.

How to check if your phone is unlocked (in 30 seconds)

On an iPhone. Open Settings > General > About and scroll to Carrier Lock. Some regions label it Network Provider Lock. Apple confirms that “No SIM restrictions” means your iPhone is unlocked. A carrier name or any other message means it’s locked.

On Android. There’s no single menu across brands. Look under Settings > About phone, or in your SIM or network settings, for a “Network lock” or “SIM lock” status. The wording varies by maker and country.

The universal test. Borrow a SIM from a friend on a different network. Insert it and restart your phone. If calls and data work, you’re unlocked. If you see “Invalid SIM” or “SIM not supported”, you’re locked. Telstra suggests this same swap test.

Ask the carrier. Dial *#06# to display your IMEI. Then ask the carrier that sold you the phone to confirm its lock status.

Carrier lock is only one of five locks

This is where travellers get caught out. “No SIM restrictions” means the carrier lock is gone. It doesn’t mean your phone is ready for a travel eSIM.

Lock	What it blocks	How to check
1. Carrier lock	Other networks’ SIMs and eSIMs	Settings (iPhone) or the SIM swap test
2. Activation Lock / account lock	Using the phone after a reset	Make sure the previous owner has removed their Apple or Google account
3. IMEI blacklist	Network access if the phone was reported lost or stolen	Check the IMEI with a carrier before buying
4. Regional hardware	eSIM entirely, on some models	Check the exact model number, not just the name
5. Network bands	Coverage on some foreign networks	Compare your phone’s bands with your destination’s networks

The regional one surprises people most. Some versions of the “same” phone ship without eSIM at all. I explain why in Why Some Regional Phone Models Don’t Have eSIM. If you’ve modified your phone’s software, read eSIM on a Rooted or Jailbroken Phone too.

Who still sells locked phones?

Lock rules differ widely by country. That matters if your phone came from overseas, or you’re buying second-hand from abroad.

Country	Current position	What it means for you
Australia	No ban. Postpaid phones are usually unlocked. Telco prepaid handsets are often locked and may carry an unlock fee.	Check any prepaid or supermarket phone before you travel
United States	The FCC waived Verizon’s 60-day unlock rule. Verizon prepaid phones stay locked for 365 days of paid service.	Unlock well before you leave
United Kingdom	Ofcom banned the sale of locked phones from December 2021.	New UK carrier phones should arrive unlocked
Canada	The CRTC’s Wireless Code bans selling locked phones. In 2025 it told Bell and TELUS their 60-day locks didn’t comply.	Ask for a free unlock if yours is still locked
Japan	SIM locks were banned in principle on phones sold from October 2021.	Older Japanese carrier phones may still be locked

Sources: Fox Business on Verizon, Broadband Breakfast on the FCC waiver, 5G Radar on Ofcom’s ban, CRTC letter to TELUS, and Japan’s Ministry of Internal Affairs and Communications.

In the US, the waiting game has got longer. Verizon customers who pay off a phone online or in the app can wait 35 days for the unlock. The UK went the other way. Ofcom found that over a third of people who stayed put blamed a locked phone, so it banned the practice.

The Australian picture

Australia has no outright ban, so it comes down to how you bought the phone. According to WhistleOut, Optus postpaid phones are generally unlocked, but Optus prepaid Android phones are locked. Telstra pre-paid phones need a network unlock to work elsewhere. Telstra says unlocking can take 7 to 10 days. amaysim says the Optus, Oppo and prepaid phones it sells are locked to the Optus network by default.

The cheap prepaid phone from the supermarket is the classic trap. It costs little at the checkout. It costs a lot more when it rejects your travel eSIM in Tokyo.

Why a locked phone hurts most when you travel

At home, a locked phone is a mild annoyance. Abroad, it decides whether you pay local rates or roaming rates.

Here’s how it usually plays out. The eSIM installs without complaint, because adding a profile isn’t the step that’s blocked. Then the phone fails to register on the local network, and nothing loads.

A post on Verizon’s community forum shows the real cost. A parent bought an iPhone 15 Pro for a daughter moving to the UK. The phone supported eSIM, but the UK eSIM wouldn’t activate because the phone was still locked. Meanwhile, the family was paying around US$10 a day for Verizon’s TravelPass.

Two more details raise the stakes:

• No physical SIM fallback. iPhones sold in the US since the iPhone 14 have no SIM tray. A locked US iPhone can’t fall back on a local physical SIM either.
• You may need to be home to unlock. One SIM provider warns that you may need to be in your carrier’s country to get the unlock done. That’s much harder from a hotel lobby.

This isn’t a new complaint. Australian consumer advocates have long argued that unlocking fees stop travellers from avoiding global roaming bill shock.

A lock is only one reason data won’t load. If your phone is unlocked and still stuck, check your settings with eSIM Connects But Nothing Loads: The APN and DNS Fix. Keeping your home SIM on as well? Read How to Prevent Home Carrier Roaming Charges While Using a Travel eSIM.

How to unlock your phone (the legitimate way)

1. Confirm it’s locked. Run the checks above before you spend time or money.
2. Find your IMEI. Dial *#06#, or look in Settings > About.
3. Contact the carrier that locked it. Apple says it can’t unlock an iPhone for another carrier. Only the carrier can.
4. Meet the conditions. Usually the phone must be paid off and the account in good standing.
5. Pay any fee. Prepaid unlocks in Australia may cost money. Postpaid unlocks usually don’t.
6. Finish the unlock. iPhones can usually set up the new eSIM once the carrier confirms. Android phones may ask for an unlock code.

Skip third-party “instant unlock” websites. Results are hit and miss, and you’re handing your IMEI to a stranger. The carrier route is slower, but it’s clean.

Buying a phone? Use this unlocked-phone checklist

Run through these before you pay, whether the phone is new or second-hand:

• Buy outright from the manufacturer or a major retailer where you can. JB Hi-Fi, Harvey Norman and The Good Guys sell unlocked phones from the big brands.
• Ask for a Settings screenshot showing the lock status, along with the IMEI.
• Check the model number, not just the model name. It tells you the region and whether eSIM is supported.
• Confirm the seller has removed their account, such as Find My on iPhone or their Google account on Android.
• Compare network bands if the phone was made for another market.

When I buy a phone, I treat “unlocked” as a claim to verify. It takes five minutes, and it protects your first day abroad.

My rule: check the lock 14 days before you fly

Fourteen days covers most carrier processing times, including Telstra’s 7 to 10 day window. It also leaves room for surprises, like a hand-me-down phone still signed into someone else’s account.

This is the order I follow before every trip:

1. Check the carrier lock status in Settings.
2. Confirm the phone supports eSIM.
3. Request an unlock if needed, and screenshot the confirmation.
4. Install the travel eSIM a day or two before departure.

If your phone passes, a BazTel eSIM installs with one tap. There’s no QR code to scan. You can browse plans for 160+ destinations, or try eSIM for the first time with a US$1 plan. New to the technology? Start with what an eSIM is.

Myths vs facts

Myth	Fact
“Unlocking a phone is illegal.”	Unlocking through your carrier is a standard, legitimate service.
“An unlocked phone works on every network.”	It still needs eSIM support and the right network bands.
“If the eSIM installed, my phone must be unlocked.”	A locked phone can install an eSIM and still refuse to connect.
“Apple can unlock my iPhone.”	Only the carrier that locked it can.
“Phones bought outright are always unlocked.”	Telco prepaid phones bought outright are often locked.

Frequently asked questions

Is carrier-unlocked the same as factory-unlocked?

Both work with any compatible network. A factory-unlocked phone was never locked. A carrier-unlocked phone was locked and later released. Once unlocked, they behave the same way.

Does an eSIM work on a locked phone?

Only an eSIM from the carrier the phone is locked to, or from a provider on that same network. A travel eSIM from another network will usually install but fail to connect.

Can I unlock my phone while I’m overseas?

Sometimes, but don’t rely on it. Some carriers need you to contact them from home, and processing can take days. Unlock before you leave.

Will unlocking erase my phone?

Usually not. On an iPhone without a new SIM to insert, Apple’s process may involve a backup, erase and restore. Back up first either way.

Are iPhones bought from Apple unlocked?

Generally yes, if you bought them outright without carrier financing. Still, confirm “No SIM restrictions” in Settings before you travel.

Does unlocking remove Activation Lock?

No. Carrier lock and Activation Lock are separate. Only the account owner can remove Activation Lock.