The Samsung Galaxy S21 Ultra is a powerhouse, but being locked to a single carrier can limit its potential. Whether you’re switching providers for better service, traveling internationally, or planning to sell your phone, unlocking it gives you the freedom to use any SIM card.
This guide walks you through everything you need to know about unlocking your Galaxy S21 Ultra—from checking its lock status to using carrier-approved methods or third-party services. In just a few steps, you’ll gain full control over your device and enjoy the flexibility of choosing the network that works best for you.
Key Takeaways
- Unlocking your Samsung Galaxy S21 Ultra allows you to use any carrier – Whether switching providers, traveling, or selling your phone, unlocking gives you complete network freedom.
- You can unlock your phone through your carrier or a third-party service – If your device meets carrier requirements, they will provide an unlock code for free. If not, a reputable unlock service can help.
- Checking if your phone is locked is simple – Insert a different SIM card, check network settings, or use an IMEI checker to confirm if your device is locked.
- Entering an unlock code is quick and easy – After obtaining an unlock code, simply insert a new SIM card, enter the code when prompted, and enjoy an unlocked phone.
- Unlocking increases your phone’s value and flexibility – An unlocked Galaxy S21 Ultra is worth more on resale, saves you from roaming fees, and ensures you can switch to the best carrier anytime. ????
Understanding Phone Unlocking
What Does It Mean to Unlock a Samsung Galaxy S21 Ultra?
Unlocking your Samsung Galaxy S21 Ultra removes the carrier restrictions, allowing you to use it with any network worldwide. This means you can swap SIM cards freely without being tied to a single provider.
Carrier-Locked vs. Unlocked Phones
- Carrier-Locked: Restricted to one network; requires an unlock code or approval to switch providers.
- Unlocked: Works with any compatible carrier by simply inserting a new SIM card.
Legal Aspects of Unlocking
The FCC (Federal Communications Commission) ensures that carriers must unlock eligible phones upon request. As long as your device is fully paid off and meets carrier requirements, unlocking is completely legal.
How to Check If Your Samsung Galaxy S21 Ultra Is Locked
Before unlocking your Galaxy S21 Ultra, it’s important to confirm whether it’s actually locked. Here are three easy ways to check:
Method 1: Using a Different SIM Card
- Turn off your phone and remove your current SIM card.
- Insert a SIM card from a different carrier.
- Power on your phone and check for a signal.
- If you see a message like “SIM Network Unlock PIN” or “Invalid SIM”, your phone is locked. If the new SIM works, it’s already unlocked.
Method 2: Checking Through Phone Settings
- Open the Settings app.
- Go to Connections > Mobile Networks > Network Operators.
- Tap Search Networks or Select Manually.
- If multiple carrier options appear, your phone is likely unlocked. If it only shows your current carrier, it may be locked.
Method 3: Using the IMEI Number
- Dial
*#06#to display your IMEI number. - Copy the number and visit an online IMEI checker (such as your carrier’s website or a trusted third-party tool).
- Enter the IMEI and check the lock status. If it says “Locked” or “SIM Restricted,” your device is still tied to a carrier.
Once you confirm the lock status, you can proceed with unlocking your Samsung Galaxy S21 Ultra and enjoy the flexibility of switching networks.
Unlocking Your Samsung Galaxy S21 Ultra Through Your Carrier
If your Galaxy S21 Ultra is carrier-locked, the easiest and most reliable way to unlock it is by requesting an unlock code from your provider. Here’s how to do it:
Eligibility Requirements
Before your carrier approves an unlock request, your phone must meet these conditions:
- The device is fully paid off (no remaining balance or contract obligations).
- The account is in good standing (no overdue payments or reported fraud).
- The phone has been active on the carrier’s network for a specific period (varies by provider).
- The device isn’t reported as lost, stolen, or blacklisted.
How to Request an Unlock Code from Major Carriers
???? AT&T
- Visit the AT&T Device Unlock Portal (Unlock an AT&T device).
- Enter your phone’s IMEI number (dial
*#06#to find it). - Fill out the request form and submit it.
- You’ll receive an email confirmation—click the link inside to confirm your request.
- AT&T typically processes unlocks within 24-48 hours.
???? Verizon
- Most Verizon 4G and 5G phones are already unlocked after 60 days of activation.
- If your phone is still locked after this period, contact Verizon customer support at *611 or through the Verizon website.
???? T-Mobile
- Open the T-Mobile App or go to T-Mobile’s Unlock Page.
- Log in and check if your device is eligible.
- If approved, follow the instructions to unlock the device.
- T-Mobile unlocks can take up to 48 hours to process.
How to Enter the Unlock Code
Once your carrier provides an unlock code, follow these steps to enter it:
- Power off your phone and insert a SIM card from a different carrier.
- Turn your phone back on.
- A message will appear: “SIM Network Unlock PIN” or “Enter Unlock Code”.
- Type in the unlock code provided by your carrier.
- Tap OK or Unlock—if the code is correct, your phone is now unlocked!
After unlocking, restart your phone and test it with the new SIM to ensure it connects to the new network.
Unlocking Your Samsung Galaxy S21 Ultra Using a Third-Party Service
If your carrier refuses to unlock your Samsung Galaxy S21 Ultra or the process takes too long, a third-party unlock service can be a faster alternative. These services provide unlock codes or software tools to remove carrier restrictions.
When to Consider a Third-Party Unlock Service
- Your carrier denies the unlock request due to eligibility issues.
- The phone was purchased second-hand and you don’t have access to the original account.
- You need a faster unlocking solution without waiting for carrier approval.
Choosing a Reputable Unlocking Service
Not all unlock services are trustworthy, so it’s important to choose a reliable provider. Look for:
✅ Positive customer reviews on Trustpilot or Reddit.
✅ Money-back guarantees if the unlock doesn’t work.
✅ Clear pricing without hidden fees.
✅ Fast processing times (most services take 24-72 hours).
✅ Support for Samsung devices and clear instructions.
Some well-known unlock services include DoctorSIM, UnlockBase, and DirectUnlocks.
Step-by-Step Guide to Unlocking Using a Paid Service
1️⃣ Find Your IMEI Number
- Dial
*#06#or check in Settings > About Phone > IMEI Information.
2️⃣ Choose a Trusted Unlock Provider
- Visit the website of a reputable unlock service.
- Select Samsung Galaxy S21 Ultra and enter your IMEI number.
3️⃣ Purchase the Unlock Service
- Follow the checkout process and provide the necessary details.
- Some services send an unlock code, while others remotely unlock the device.
4️⃣ Enter the Unlock Code (if applicable)
- Insert a SIM card from a different carrier.
- When prompted, enter the unlock code provided.
- Confirm and restart your device.
5️⃣ Test the New Network
- Check if your phone detects the new carrier.
- Make a call or browse the internet to ensure full functionality.
Using a third-party service is a simple way to unlock your phone when carrier options aren’t available. Just be sure to pick a trustworthy provider to avoid scams.
Unlocking Samsung Galaxy S21 Ultra with Unlock Software or Apps
Overview of Unlocking Software Tools
Some third-party software tools claim to unlock carrier restrictions on the Samsung Galaxy S21 Ultra by modifying system settings. These programs often require a PC connection and specialized software, such as Samsung Unlock Tool, SamKey, or Octoplus Box.
Risks and Precautions
⚠️ May void your warranty or violate carrier terms.
⚠️ Risk of malware or scams if using unverified software.
⚠️ Complex process requiring technical knowledge.
⚠️ Not always permanent—some methods may relock after a factory reset.
Step-by-Step Guide (If Applicable)
1️⃣ Download a Trusted Unlock Tool from a reputable source.
2️⃣ Enable Developer Mode & USB Debugging
- Go to Settings > About Phone > Software Information > Tap Build Number 7 times.
- In Developer Options, enable USB Debugging.
3️⃣ Connect Your Phone to a PC using a USB cable.
4️⃣ Run the Unlock Software and follow on-screen instructions.
5️⃣ Restart Your Phone and insert a new SIM to test.
Due to security risks, unlocking via software is not recommended unless you fully understand the process. Carrier unlocking or third-party services are usually safer options.
Unlocking Samsung Galaxy S21 Ultra with an Unlock Code
How to Obtain an Unlock Code
You can get an unlock code from:
✅ Your Carrier – If eligible, request it through their website or customer support.
✅ Third-Party Unlock Services – Paid services like DoctorSIM or UnlockBase provide codes for non-eligible devices.
Steps to Enter the Unlock Code Correctly
1️⃣ Insert a SIM card from a different carrier.
2️⃣ Turn on your phone—a prompt will appear: “SIM Network Unlock PIN.”
3️⃣ Enter the unlock code provided by your carrier or service.
4️⃣ Tap Unlock and restart your device.
Troubleshooting Common Issues
⚠️ Wrong Code Error – Double-check the code and retry. Too many failed attempts may lock the phone.
⚠️ No Network After Unlocking – Go to Settings > Connections > Mobile Networks and select the correct carrier.
⚠️ “SIM Network Unlock Unsuccessful” – Contact the provider for assistance or request a new code.
Once unlocked, your Galaxy S21 Ultra is free to use with any carrier! ????
What to Do After Unlocking Your Samsung Galaxy S21 Ultra
1️⃣ Restart and Insert the New SIM Card
- Power off your phone and remove the old SIM.
- Insert the SIM from your new carrier.
- Turn your phone back on—if you see a signal, the unlock was successful!
2️⃣ Set Up APN Settings for the New Carrier
- Go to Settings > Connections > Mobile Networks > Access Point Names (APN).
- Select your carrier or tap Add to enter the correct APN details (available on your carrier’s website).
- Save and restart your phone.
3️⃣ Test Your New Network
✅ Make a call and send a text.
✅ Use mobile data to check internet access.
✅ Ensure features like 5G, Wi-Fi calling, and hotspot work properly.
Once everything runs smoothly, your Galaxy S21 Ultra is fully unlocked and ready to use with any carrier! ????
Troubleshooting Common Unlocking Issues
1️⃣ “SIM Network Unlock PIN” Error
- This means your phone is still locked. Double-check the unlock code and enter it carefully.
- If the issue persists, contact your carrier or unlock service for a new code.
2️⃣ Unlock Code Not Working
- Ensure you entered the correct code without extra spaces or digits.
- If too many incorrect attempts were made, your phone may be permanently locked—contact Samsung or your carrier for assistance.
3️⃣ No Network Service After Unlocking
- Go to Settings > Connections > Mobile Networks and select your carrier manually.
- Set up APN settings (available on your carrier’s website).
- Restart your phone and try again.
Benefits of an Unlocked Samsung Galaxy S21 Ultra
✅ Freedom to Switch Carriers – Use any compatible SIM card worldwide.
✅ No Expensive Roaming Fees – Save money by using local SIM cards when traveling.
✅ Higher Resale Value – Unlocked phones attract more buyers and sell for a better price.
Once unlocked, your Galaxy S21 Ultra becomes a truly flexible device, giving you control over your network choices! ????
FAQs About Unlocking Samsung Galaxy S21 Ultra
1️⃣ Will an unlocked Galaxy S21 Ultra work on any carrier?
Yes! Once your Samsung Galaxy S21 Ultra is unlocked, it can work with most carriers worldwide. In the U.S., models like SM-G998U1 (factory unlocked version) are compatible with AT&T, Verizon, T-Mobile, and many MVNO carriers like Mint Mobile, Metro, and Cricket Wireless. Just make sure your new carrier supports the phone’s network bands.
2️⃣ Can you unlock a Samsung Galaxy S21 Ultra to any network?
Yes, but it depends on how the phone was locked. If it was purchased from a carrier, you need to meet their unlock requirements (fully paid off, active for a set period, etc.). If your carrier refuses to unlock it, you can use a third-party service to obtain an unlock code. Once unlocked, you’re free to use any compatible SIM card.
3️⃣ Can a carrier-locked Samsung phone be unlocked?
Absolutely! Carriers typically lock phones to their network, but they are required to unlock them if you meet their conditions. This includes paying off any remaining balance, completing your contract, and ensuring the device isn’t reported lost or stolen. If your carrier denies the request, third-party unlocking services offer another way to get it done.
4️⃣ What is the free network unlock code for Samsung?
There’s no universal “free” unlock code, but if your carrier grants you an unlock, they will provide a unique unlock code for your device. If you already have the code, you can enter it using this method:
- Dial #7465625638UNLOCKCODE# or #0111*UNLOCKCODE# (replace UNLOCKCODE with the code provided).
- Press call/send, and your phone should unlock instantly.
5️⃣ What is the 8-digit network unlock code?
The 8-digit network unlock code, sometimes referred to as a PUK (Personal Unlock Key), is used to unlock a SIM card that has been blocked due to too many incorrect PIN attempts. If your phone asks for this code, contact your carrier—it’s tied to your SIM card, not your device.
6️⃣ What is the 16-digit network unlock code?
For some Samsung devices, the SIM Network Unlock PIN can be 8 to 16 digits long. This code is used to unlock a phone tied to a specific carrier, allowing it to work with other networks. You can request this code from your original carrier by providing your phone’s IMEI number or purchase it from a trusted third-party unlock service.
Once unlocked, your Samsung Galaxy S21 Ultra becomes a fully flexible device, ready to work with any network worldwide! ????
TL;DR
Unlocking your Samsung Galaxy S21 Ultra lets you switch to any carrier, avoid roaming fees, and increase resale value. You can check if your phone is locked by inserting a different SIM, checking network settings, or using an IMEI checker. If locked, request an unlock code from your carrier (if eligible) or use a trusted third-party service. Entering the unlock code is simple—just insert a new SIM, type in the code, and restart your device. Once unlocked, set up your new carrier’s APN settings to ensure full network compatibility. Enjoy the freedom of an unlocked phone!