Mobile Number Porting Problems: What Is a Split Port and How Do You Fix It?

A split port happens when your mobile number transfer only completes properly in some parts of the network. 

Your new SIM may show the correct number. Outgoing calls might work. Mobile data might be fine. 

But incoming calls from certain networks go nowhere. 

Texts may still land on the old SIM. 

Bank verification codes vanish. 

It’s called a split port because, from the customer’s point of view, one phone number seems to be living in two places at once. 

The important bit: this is usually a provider-side routing problem, not something you can fix by repeatedly resetting your phone. 

“I Can Ring Everyone. Nobody Can Ring Me.” 

Sam switched provider on a Tuesday. 

By lunchtime his new SIM showed his old number. 

He made a call. 

Perfect. 

Sent a text. 

Also fine. 

Job done, he thought. 

Then his wife tried calling him. 

“Number not recognised.” 

A colleague on the new network could reach him, but his dad on another provider couldn’t. Security codes weren’t arriving either. 

That’s classic split-port behaviour. 

Recent UK provider support forums show exactly this pattern: customers able to make calls and send messages while incoming traffic from other networks fails or continues routing towards the previous provider.  

What’s Actually Been Split? 

Your number doesn’t physically move from one SIM to another like a contact copied between phones. 

Providers have to update network routing so calls and messages from different operators know where your number now lives. 

During a normal port, those records get updated. 

During a split port, part of that process has not completed correctly. 

That’s why replacing the handset often achieves precisely nothing. 

The dodgy bit isn’t sitting in your pocket. 

It’s in the routing between networks. 

Give the Porting Window a Chance First 

On the actual transfer day, service can be a bit messy while the number moves. 

Restarting the old and new phones or switching the SIM off and back on can help devices register with the updated network. 

EE’s community support team currently describes temporary split service during a transfer and recommends restarting the old and new SIMs while records update.  

But there is a limit to “just give it time”. 

Ofcom says a normal mobile port should be completed within one working day after the new provider receives the PAC. Any loss of service should not exceed one working day, and customers must be offered compensation when porting is improperly delayed.  

So if you’re still split after the expected transfer window, stop endlessly rebooting. 

Call the provider. 

Contact the New Provider First 

Ofcom advises customers experiencing refused or delayed number porting to contact their new provider.  

Tell them exactly what works and what doesn’t. 

For example: 

• Outgoing calls work  
• Incoming calls from Vodafone fail  
• Calls from the new provider work  
• Incoming SMS fails  
• Old SIM still receives calls  

Use the phrase possible incomplete or split port. 

That gives support a much better clue than saying “my phone is broken”. 

Ask them to escalate it to their number-porting or technical team. 

In cases discussed by Three’s support community, fixing a split port can require the new provider to contact the previous network internally and request the missing porting information.  

That isn’t something changing an APN can fix. 

Don’t Keep Requesting New PACs 

A PAC is valid for 30 days and is used to initiate the transfer.  

Once the port is already underway, repeatedly requesting new codes isn’t normally the solution to incomplete routing. 

Let the providers fix the existing transfer. 

Also don’t cancel the old service manually before the port unless your provider specifically tells you to. 

The PAC process is designed to coordinate the switch. 

More manual intervention does not always mean more progress. 

Sometimes it just means more opportunities for chaos. 

Where Talk Home Mobile Fits 

Talk Home Mobile currently says a port request submitted before 5pm should transfer by the next working day. Requests made after 5pm can take two working days.  

Talk Home also says its systems monitor delayed transfers and credit the equivalent of 1GB of allowance for each day of loss of service while the issue is being fixed. If the switch still hasn’t completed after seven days, customers are told to contact support.  

If your number has visibly moved to Talk Home but calls or texts only work in one direction, report the exact symptoms rather than treating it as a normal handset fault. 

A split route needs network-side attention. 

Final Thoughts 

A split port can make a perfectly good phone look completely confused. 

Outgoing works. 

Incoming doesn’t. 

One network can reach you. 

Another thinks your number has vanished. 

Test calls and texts from more than one network if possible, write down what fails, then give that information to your new provider’s porting team. 

And once you’ve established that calls from half the country aren’t being routed correctly, stop factory-resetting your phone. 

The poor thing didn’t port your number.