Use the O2 network status checker to see if there’s a known network connection problem in your area, or to report an unknown issue to us. From here, you’ll be able to subscribe to updates using Keep Me Posted. 

If there’s no known issue, try manually resetting your device by: 

• Turning your phone off and on 
• Making sure mobile data is turned on in your settings
• Choosing the O2 network manually in your settings
• Resetting your network settings (this will also reset Wi-Fi networks and passwords, cellular settings, VPN and APN settings that you’ve used before) 

Instructions on how to take these steps can be found using our device-specific trouble-shooter here.

If you think there might be an issue with your device or sim: 

• Try your sim in a different O2 phone 
• Try a different O2 sim in your phone  

If you need more help with solving signal issues, visit the O2 Community where our Gurus will be able to offer more advice. 

When you have no signal, you can use Wifi to call and message instead.

If it's available with your device, you can use our Wifi Calling service make calls, receive calls and send and receive text messages when you have no signal. We also have over 16,000 O2 Wifi hotspots available to connect to for free, which offer speeds up to 10 times faster than a normal mobile connection.

The power of 5G on personal and business devices will give everyone a better and more reliable connection in extra busy places, delay-free downloads and buffer-free streaming. But it’s 5G’s impact on the world around us that’s even more exciting. This new technology has the power to connect buildings, transport and services in ways we’ve never seen, completely revolutionising everything from the way traffic flows on our roads, to the way we receive health care.

We now have 5G in parts of most major UK towns and cities, as well as lots of smaller towns and villages. Find out more about O2 5G.

O2 Business customer? Find out how 5G can transform your business.

Take a look at our 5G explained page for FAQs and more information on how to get 5G.

2G 

Second generation mobile network known as GSM. Simply put, 2G allows you to send text messages.

3G 

The third generation of mobile phone technology, offering better coverage for voice calls and text messaging, as well as providing faster access to the internet than our 2G network. We’ll be switching off our 3G services in 2025.

3.5G 

Also known as HSDPA (High Speed Data Packet Access), 3.5G provides faster data rates than 3G.

4G 

The fourth generation of mobile phone technology. With 4G, using the internet on your phone is even quicker, with speeds 5-7 times faster than 3G. If you have a 4G ready phone, but you’re not in a 4G area, you’ll still be able to use 3G until it’s switched off in 2025. Learn more about 3G switch off.

5G

5G will give everyone a better and more reliable connection in extra busy places, delay-free downloads and buffer-free streaming.

Cellular network 

The radio network used to send and receive calls and messages, and use the internet.

Wifi 

You can connect to the internet using wifi, to browse the web, download applications, or send and receive emails, without using your 3G or 4G data.

O2 Wifi 

A fast, free wifi service available to everyone. You just download the app, and you’ll be connected to O2 Wifi whenever you’re in a hotspot.

What is Wifi Calling?

Some phones can use wifi to make voice calls. Wifi Calling (also called Voice over Wifi or VoWifi), helps you make and receive calls even if you can't connect to the mobile network, like when you're on the London Underground. When connected to wifi, you can just dial the number you want to call like normal.

What is 4G Calling?

Some phones support 4G Calling (also called Voice over LTE or VoLTE). 4G Calling lets you make clearer voice calls using our award-winning 4G network. If 4G Calling is available, you can just dial the number you want to call like normal. You can check 4G Calling coverage with our coverage checker.

O2 Pocket Hotspot 

A portable gadget that connects you and up to four other people or devices to the internet, when there’s O2 mobile data coverage. The O2 Pocket Hotspot automatically connects to our mobile network as soon as you insert a Pay As You Go sim.