What's my phone number?

Your phone number is the set of digits that identifies your mobile line. It’s how people call or text you and is often needed when setting up apps, accounts or services.

In the UK, a mobile phone number has 11 digits and usually starts with 07. This confirms it’s a mobile number, not a landline.

Some people can memorise their number, but, with so many digits, it can be hard to remember it in full. So, if you’re not sure what yours is, these steps are the easiest ways to check.

The steps might be slightly different depending which version of iOS you’re using, as Apple has changed menu names over time.

1. Open Settings

2. Select Mobile Service

3. Look for My Number if you use dual SIM or an eSIM, you may see more than one number listed.

If you’ve recently upgraded to a new iPhone, such as iPhone 17 Pro Max, this is usually the quickest way to check your number once the SIM or eSIM has activated.

1. Open Settings

2. Select Phone

3. Your number will appear at the top next to My Number

• Open the Contacts app and check the contact card at the top of the list

• Call or message another phone you have access to and ask the recipient to read back the number shown on their screen

This can happen if the SIM hasn’t fully registered yet.

Android menus can vary by manufacturer, but the steps are usually similar.

1. Open Settings

2. Choose About phone or About device

3. Select Status or SIM status

4. Your phone number should be listed here

Many Android phones also have a search bar in Settings. Typing “phone number” can be the quickest route.

If you’re setting up a new Android device, like the Samsung Galaxy S25 Ultra, your number may not appear until the device has fully connected to the network.

If your phone doesn’t show your number, your mobile network can usually help.

Text NUMBER to 2020 and you’ll receive a reply with your number.

Most networks show your number in:

• Your online account

• Their mobile app

• Your phone’s settings

Some networks also support short codes or text services, but these can vary by plan and SIM type. If you’re unsure, signing in to your account is usually the most reliable option.

If the options above don’t work, you can also try:

• Call or text someone – if caller ID is enabled, your number will appear on their screen

• Check your SIM pack – your number is often printed on the original packaging

• Restart your phone – this can help if the SIM hasn’t fully connected yet

Sometimes a phone doesn’t show a number because:

• The SIM hasn’t fully activated

• The phone hasn’t synced with the network yet

Restarting the device or reinserting the SIM usually fixes this. If not, your mobile network can help get things sorted. 

If you still need help finding your number, your network’s support team can talk you through the next steps.

If you’re setting up a new phone or SIM, O2 has a range of SIM Only plans and the latest phones, including iPhone and Samsung devices.

You can keep your number when you switch, or get started with a new one if that suits you better. Once your SIM or eSIM is active, checking your number is quick using the steps on this page.

Explore O2 phones and SIM Only plans to find what works for you.

_{Last updated: 18/03/2026}