Before You Go to China: Understanding Locked and Unlocked Phones

Before traveling to China, it’s important to understand the difference between a locked and unlocked phone, especially if you plan to use a local SIM card or an international eSIM.

A locked phone is restricted to a specific carrier. This means it can only work with SIM cards from the mobile network that originally sold the device. For example, if your phone is locked to a carrier in your home country, inserting a Chinese SIM card or activating a China travel eSIM may not work. Many carrier contracts lock phones to prevent users from switching networks before the contract ends. Using a locked phone while traveling can lead to limited connectivity, higher roaming fees, or complete loss of mobile data.

An unlocked phone, on the other hand, can be used with SIM cards or eSIMs from any carrier worldwide. This gives travelers full flexibility to choose local Chinese SIM cards or international eSIM plans, helping reduce costs and ensuring reliable internet access. Unlocked phones are ideal for China, where access to maps, translation apps, ride-hailing services, and messaging apps is essential.

Before your trip, check with your carrier to confirm your phone’s lock status. An unlocked phone ensures a smoother, more connected travel experience in China.

What does an unlocked phone mean?

Absolutely! An unlocked phone is built to work with any carrier’s network, making them versatile enough to meet any wireless needs you have. This freedom allows you to enjoy improved coverage and potentially better plan prices, offering a world of possibilities to enhance your mobile experience without worrying about the compatibility issues that often come with locked devices.

What does an unlocked phone mean?

  • Unlocked phones allow you to effortlessly swap SIM cards from different carriers into your phone, providing unparalleled freedom and choice in selecting your mobile service. This enables you to adapt your phone usage to your lifestyle, whether it’s optimizing for cost, coverage or traveling internationally, ensuring your mobile needs are always met with the perfect plan.

    What is a locked phone?

    • Imagine a phone that’s loyal to only one carrier, not by choice but by design. That’s a locked phone for you. It can’t switch until it’s officially unlocked, tethering you to one carrier’s network, plans and coverage areas, regardless of your needs. This restriction can limit your ability to seek out more competitive rates or better coverage from other providers, potentially keeping you from optimizing your mobile experience based on your personal or travel requirements.

      What is GSM unlocked?

      • A GSM unlocked phone can connect with carriers on the Global System for Mobile Communications (GSM) standard, the primary technology for mobile networks globally. Ideal for international travelers and those who wish to easily switch carriers, these phones liberate users from the constraints of being tied to a single network and accept SIM cards from any GSM service provider, including Ultra Mobile.

        A GSM Unlocked phone means a phone can now use any SIM cards of GSM network (such as AT&T and T-Mobile). It’s a term common in the phone market.

        Usually, an unlocked GSM phone is more expensive than a locked one. Most of people prefer buying a locked phone and then unlock it with a small fee to save money.

        How to Know if My Phone is GSM Unlocked?

        Determining if your phone is GSM unlocked is very easy, and there are 3 ways for you to find out.

        1. Check Settings (for iPhone and Android)

        iPhone

        For iPhone users, go to the Settings app and navigate to Cellular > Cellular Data. If there's an option to select or change the Cellular Data Network, this means that your phone is likely GSM unlocked.

        Android Phones

        For Android users, go to the Settings app and navigate to Connections > Mobile Networks > Network Operators. The exact path might differ depending on your Android device model, but it will be similar.

        In this menu, tap on the Search Now button and a scan for available carriers will be run. If you can connect to different networks, this means your phone is GSM unlocked.

        2. Switch SIM Cards

        • A more reliable way of checking a phone's unlock status is to enter a SIM card from a different carrier. By doing this, you can check if your phone can successfully connect to another network.
        • If it can, and you're able to send texts and make phone calls, this indicates that the phone has been GSM unlocked.

        3. Using IMEI Checker

        iPhone

        For iPhone users:

        • Check the unlock status in the same way as you do with the Samsung phones
        • Then, dial *#06# to check the eSIM capacity.
        • In case your device is eSIM-compatible, you should be able to view your device's eSIM unique identification number (EID)

        Android Phones

        • Going to Settings
        • If in Settings you see a search bar, typing in "IMEI", and the option "IMEI information" (or similar) should show up (otherwise, you will need to go to About phone > Status).
        • Tap "IMEI information"
        • If the "IMEI (eSIM)" is available, it should mean that your device supports eSIM.

        GSM Unlocked vs CDMA Unlocked, What's the Difference?

        You might be wondering what the difference between GSM unlocked and CDMA unlocked is. Although they're very similar, there are some notable differences to keep in mind.

        A GSM phone stores all of your network data on the SIM card so to unlock the phone, you actually have to unlock the SIM card. Doing this is as simple as getting an unlock code, typing it into the phone, and unlocking it.

        A CDMA phone stores all of your network data on the phone's hardware, not the SIM card. So, unlocking a CDMA phone usually requires computer software.

        GSM Unlocked vs Fully Unlocked (Factory Unlocked)

        This is another question we see a lot, and the difference between these is very clear.

        A GSM unlocked phone has been unlocked from a carrier at some point, meaning that it was previously locked.

        On the other hand, a fully unlocked (factory unlocked) phone has never been locked to a carrier and was distributed without a carrier lock.

        If you're using a prepaid or pay-as-you-go plan, there's a good chance your phone is already unlocked. The FCC mandates that carriers unlock prepaid phones within a year of activation.

        For Android Users:

        Android network settings screen
        1. Go to Settings
        2. Tap on Connections (this might vary as Networks, Mobile Networks, or Cellular Networks depending on your device)
        3. Select Network Operators
        4. If a list of available networks shows up, your phone is likely unlocked. However, if only one or no network options are presented, your phone is probably locked.

        For iPhone Users:

        iPhone cellular settings screen
        1. Go to Settings
        2. Select Cellular
        3. If you see Cellular Data as an option under the Cellular menu, congratulations, your iPhone is unlocked.
        4. If the Cellular Data Network option isn't visible, then your device is still locked.

        Contact Your Wireless Carrier:

        Contact your carrier for unlock status

        Another reliable method is to directly contact your carrier. They can tell you whether your phone is unlocked and, if necessary, unlock it for you.

        You'll need to provide your IMEI number, which can be found by dialing "*#06#" on your phone. Alternatively, visiting your carrier's store or checking via their website or app are also viable options.

        SIM Card Swap Test:

        SIM card swap test

        A practical way to check your phone's status is by swapping SIM cards. Here's how:

        1. Power off your phone and locate the SIM card tray. You might need a SIM ejector tool or a paperclip to open it.
        2. Remove your current SIM card and replace it with one from a different carrier.
        3. Power your phone back on. If it requests a code to unlock the SIM, your phone is locked to your carrier.
        4. Conversely, if you can make calls and use the phone normally, it's unlocked.

        How to unlock a phone?

        • Unlocking your phone allows you to switch carriers and use your device internationally with ease. For most carriers, including Verizon and AT&T, the process begins after your phone is fully paid off and involves a waiting period — typically 60 days for Verizon and a similar timeframe for AT&T. After meeting your carrier’s requirements, you can usually request an unlock online or by contacting customer service. Confirmation of unlocking is often communicated through email or direct contact, ensuring your device is ready for use on any compatible network

          What you'll need to unlock your phone

          To unlock your phone, you'll need the following things:

          • 1

            Account holder's name and current account number

          • 2

            Your device's IMEI number (dial *#06# on your keypad to retrieve this number) or go to Settings > About

          • 3

            Your current phone number

          • 4

            The account holder's Social Security Number and/or password. Typically, you'll need your Social Security Number if you're trying to unlock online. In other instances, such as when speaking with a representative, your account number or password will work.

          • 5

            A completed contract and/or device payment plan

          All Steps to Unlock a Phone

          How to unlock iPhone

          1. 1
            Make sure you're eligible to unlock your phone
            Haven't paid off your phone or signed up for a long-term contract? You may not be able to unlock your phone just yet.
          2. 2
            Contact your carrier
            Either via phone, email or online request form.
          3. 3
            Verify your identity with your current carrier
          4. 4
            Wait for confirmation that they've begun the unlocking process
            This process may take a few days to complete.
          5. 5
            Complete the unlocking process per their instructions
            Every carrier may have slightly different instructions for unlocking.
          6. 6
            Receive confirmation that your phone is unlocked
            You're good to go ahead and switch carriers at this point!

          How to unlock Android

          1. 1
            Make sure you're eligible to unlock your phone
            Haven't paid off your phone or signed up for a long-term contract? You may not be able to unlock your phone just yet.
          2. 2
            Contact your carrier
            Either via phone, email or online request form.
          3. 3
            Verify your identity with your current carrier
          4. 4
            Wait for confirmation that they've begun the unlocking process
            This process may take a few days to complete.
          5. 5
            Complete the unlocking process per their instructions
            Every carrier may have slightly different instructions for unlocking.
          6. 6
            Receive confirmation that your phone is unlocked
            You're good to go ahead and switch carriers at this point!

          Conclusion

          Using an unlocked phone is essential when traveling to China, as it allows your device to connect freely to local mobile networks or international eSIM services. GSM-unlocked phones are the most common and widely compatible, making them a reliable choice for travelers. Although this guide focuses mainly on GSM devices, many of the same principles also apply to CDMA phones, meaning users of different phone types can still benefit from unlocking their devices before departure.

          An unlocked phone gives you the flexibility to avoid expensive roaming fees, use local SIM cards, or activate a travel eSIM for stable data access in China. If your phone is currently locked to a carrier, the unlocking process is usually straightforward. Your mobile carrier can help you unlock your device through customer support channels such as live chat, email, or a hotline. Unlocking your phone ahead of time ensures a smoother, more connected travel experience in China.