Why Are Some Texts Still Going to My Old SIM After Porting?

Your calls work.

Your data works.

Your new SIM looks completely fine.

Then someone sends you a text and somehow it arrives on the old SIM.

This is one of the stranger problems after switching mobile providers.

It happens because SMS routing can update differently from voice routing.

Your number transfer is not just one change.

Different services need to recognise that your number now belongs to a new network.

The Verification Code That Went Missing

Amir switched providers and moved his number.

Friends could text him.

Normal messages worked.

Then he tried logging into his banking app.

The verification code never arrived.

After checking both phones, he found it.

The code had gone to the old SIM.

Why?

Because some messaging routes were still pointing towards the previous provider.

Why Can SMS Be Delayed After Porting?

Text messages travel through SMS routing systems.

When someone sends an SMS, the sender’s network needs to know where that number currently belongs.

After a port, those routing records need updating.

If the sender’s network still has old information, messages can temporarily follow the old path.

Why Do Some Texts Work But Others Fail?

Because not all SMS traffic comes from the same place.

A message from your friend on another UK network may use one route.

A bank’s automated verification message may use another.

A company’s messaging platform may have different routing agreements.

That is why you can receive normal texts while important codes disappear.

How Long Does SMS Porting Take?

Most issues resolve quickly.

But if important messages continue going to the old SIM after the port has completed, your new provider should investigate.

Do not repeatedly request verification codes.

Some banks temporarily block repeated attempts.

Try These Fixes

Restart Your Phone

A fresh network registration can help.

Remove the Old SIM

If you are using dual SIM:

• Remove the old SIM temporarily
• Restart the phone
• Test again

Ask Someone to Send a Test SMS

Test from:

• Another mobile network
• Another phone

This helps identify whether the issue is general or service-specific.

Contact Your Provider

Give them:

• Your number
• Port date
• Example senders failing
• Whether old SIM receives messages

What About iMessage and RCS?

Modern messaging adds another layer.

Apple’s iMessage and Android’s RCS can sometimes create confusion after changing SIMs.

If your phone number changes networks, make sure:

• iMessage is activated correctly
• RCS is registered correctly
• Old devices are signed out if necessary

These services are internet-based, but the phone number verification behind them can still be affected by a recent port.

Where Talk Home Mobile Fits

Talk Home Mobile supports number transfers through PAC switching.

If SMS routing problems appear after moving your number, Talk Home can investigate whether the port completed correctly and whether additional network support is required.

Before contacting support, note:

• Which messages fail
• Which networks send them
• Whether calls work
• Whether the old SIM receives them

Final Thoughts

A number transfer is not just moving a SIM.

Voice calls, SMS and online verification services can update through different systems.

That is why one part can work while another still behaves like nothing changed.

If texts keep going to your old SIM, do not panic.

Your number has not duplicated.

The message route simply needs to catch up.