Three SIM Activation Not Working? (Quick Fix Guide)

Is your Three SIM activation not working after making the switch? We’ve got you covered.

You’ll know that you have an issue with your SIM activation since you’re going to see messages like “No Service” or “Invalid SIM” on your screen. 

To fix your Three SIM not activating issue, make sure that the contacts are clean, and the SIM is inserted properly into your phone. You also want to double-check that the SIM is activated and ready for use.

Let’s explore the most efficient solutions to your issue!

Three SIM Activation Not Working – 8 Foolproof Solutions

Why is my Three SIM not working? There are many possible reasons why this occurs.

So, before you attempt any of the solutions below, make sure that your phone has good cellular and WiFi signal strength so you don’t run into more issues.

#1: Reseat and Clean Your Three SIM

One of the simplest solutions is to ensure that your SIM card is inserted properly into your phone.

While you’re at it, you also want to check if the contacts are clean since dust and dirt will interfere with the connection.

To reseat and clean your Three SIM, here are the steps you need to follow:

1. Take out your Three SIM from the SIM tray or slot.
2. Use a soft cloth or cotton swab to wipe the metal contacts of your SIM.
3. Check if there are any cracks or signs of damage on your SIM.
4. Put your SIM back into the tray.
5. Make sure that it fits snugly.

Tip: It’s not necessary that you need to switch off your phone when you take out and return your SIM card.

#2: Get Your PUK Code and Use It If Your SIM is Blocked

If you have entered the wrong PIN code three times in a row, your Three SIM is going to be blocked.

It won’t continue with the activation, and you won’t be able to complete the activation process until your SIM is unblocked.

Here’s how to get your PUK code and use it:

1. Check the SIM card packaging for the PUK code.
2. If you can’t find it, contact Three Support, who will provide your code.
3. To enter your PUK code, Turn on your phone.
4. Wait for the prompt to enter your PUK code to appear.
5. Type your PUK code.
6. Tap the Enter button.

If you enter the correct code, your SIM will be unblocked, and the activation can proceed, allowing your phone to connect to the Three network.

However, if you’re still having issues with activation, you’ll need to look at the other steps below.

#3: Ensure Your Phone is Compatible with Three’s Network

A major reason why your SIM won’t activate is your phone is not compatible with Three’s network.

You want to make sure that your phone supports the frequency Three is using so it connects to the network.

Here’s how you do it:

1. Go to a third-party compatibility checker site like WillMyPhoneWork.net.
2. Choose the brand of your phone.
3. Select the specific model of your phone.
4. Select the sub-model.
5. In the Country option, choose the United Kingdom.
6. Under Carriers, select Three or 3.
7. Click the Search button.
8. See if your phone gets the check marks that indicate compatibility.

Note: If you see “X” marks under 3G and 4G, your phone is not compatible with Three, and you’ll need to use a different one.

#4: Set Your Phone to Connect to Three Manually

There are instances when your phone will not automatically connect to Three’s network.

This usually happens when you switch from one network to another, and your phone does not recognize it right away.

You’re going to need to set your phone to connect to Three manually, here’s how to do it:

iPhone:

1. Open your phone’s Settings menu.
2. Tap on the Cellular or Mobile Data option.
3. Choose Network Operators.
4. Tap on the Manual option.
5. Select Three or 3 from the list of networks.

Android:

1. Go to your phone’s Settings.
2. Select Network and Internet.
3. Tap on Mobile Network.
4. Choose Network Operators.
5. Tap the Manually Search for Networks option.
6. Select Three or 3.

Note: We recommend you restart your phone after manually selecting the network to refresh the connection.

#5: Check for a Carrier Settings Update

Whenever you’re moving from one network to another, your phone might not have the latest settings.

There are instances when you need to download the latest settings to get your phone to work well with your carrier, which, in this case, is Three.

iPhone:

1. Go to your phone’s Settings.
2. Tap on the General menu.
3. Select About.
4. Navigate to the Carrier Settings section.
5. If an update is available, it will say “Carrier Settings Update Available”.
6. Tap on Download and Install.

Android:

1. Open your phone’s Settings.
2. Go to System.
3. Select System Updates.
4. If an update is available, it will say “Carrier Settings Update Available”.
5. Tap the Download button.

Pro Tip: For both types of devices, you want to make sure that they are connected to a stable and reliable internet connection, such as WiFi.

#6: Activate Data Roaming on Your Phone

Data roaming is not just a useful feature when you’re abroad. There’s also a way to use it when you’re in the country, especially when you’re in an area of weak or no signal.

To activate data roaming on your phone and activate your SIM, follow these steps:

iPhone:

1. Go to your phone’s Settings.
2. Select Cellular or Mobile Data.
3. Tap on Cellular Data Options.
4. Choose Data Roaming.
5. Toggle the switch to the On position.

Android:

1. Open your phone’s Settings app.
2. Select Network and Internet.
3. Go to Mobile Network.
4. Tap on Data Usage.
5. Select Data Roaming.
6. Toggle the switch to the On position.

Note: You may incur some added costs, so do this as a last resort.

#7: Check Your SIM’s Activation Status

There are instances when you did not do the SIM’s activation properly, or it’s taking much longer than expected.

You want to check the status and perform the steps on how to activate Three SIM. Here’s how to do these steps:

Check your SIM’s activation status:

1. Go to the Three website and sign in to your account.
2. Go to the My Account section.
3. Click on SIM and Devices.
4. Check if the status says “Active”.
5. If it says “Pending”, you’re going to have to wait or proceed to the next step.

Activate your Three SIM:

1. Remove the Three SIM card from your phone.
2. Restart your phone.
3. Reinsert the SIM into your phone.
4. Switch on your phone.
5. Wait for your phone to connect to the network.
6. You will receive a text message from Three confirming the activation.

Tip: Activation time takes between 24 to 72 hours, so be patient.

#8: Order a New SIM If the SIM You Received is Damaged or Faulty

If none of the above solutions work, there’s a good chance you got a faulty SIM. If this is the case, you need to get a new SIM card from Three and activate it.

Here’s how to do it:

1. Login to your Three account online.
2. Go to My Account.
3. Select SIM and Devices.
4. Click on Order a Replacement SIM.
5. Type in your details and select your preferred delivery method.
6. Wait for your new SIM to arrive.

Note: After your SIM arrives, you’re going to need to activate it using the steps described in #7.

It’s also possible to get your replacement SIM by visiting a Three store. When you go for this option, you need to bring your ID and proof of address.

#9: Reset Your Phone’s Network Settings

One of the more advanced methods to do if your Three SIM still refuses to activate is to reset your phone’s network settings.

This will remove all the network-related data on your phone. It will also fix glitches or errors that prevent your SIM from activating.

iPhone:

1. Open your phone’s Settings.
2. Tap on General.
3. Select Reset.
4. Tap on Reset Network Settings.
5. Tap on it again to confirm.

Android:

1. Go to your phone’s Settings.
2. Select System.
3. Tap on Reset Options.
4. Choose Reset WiFi, Mobile, and Bluetooth.
5. Tap on Reset Settings.
6. Tap on Reset Settings again to confirm.

Important: Resetting your phone’s network settings will not delete any of your apps, photos, or data.

#10: Change Your APN Settings

If all these solutions fail, you want to change your APN settings to use the latest ones for Three.

Some of these are incorrect or outdated, which can cause problems with your SIM activation and connection.

iPhone:

1. Go to your phone’s Settings.
2. Tap on Cellular.
3. Select Cellular Data Network.
4. Tap on APN.
5. Change the settings, and tap Save.

Change the settings to these values:

• APN: three.co.uk
• Username: (blank)
• Password: (blank)

Android:

1. Open your phone’s Settings.
2. Select Network and Internet.
3. Tap on Mobile Network.
4. Select Advanced.
5. Choose Access Point Names
6. Tap the + button to add a new APN.
7. Enter the settings, and tap Save.

Enter the following APN settings:

• Name: Three
• APN: three.co.uk
• Username: (blank)
• Password: (blank)
• Server: (blank)
• MMS proxy: (blank)
• MMS port: (blank)
• MCC: 234
• MNC: 10
• Authentication type: None

Quick Recap

If your Three SIM activation not working, you need to fix it quickly so you can continue to use your phone. You want to check your SIM’s activation status and reactivate it. Setting your phone to connect to Three manually also helps in activating your SIM.

Fore more Three troubleshooting guides, visit our blog!

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