Coverage Guide Updated January 2026

O2 Signal Problems: Coverage & Fixes

Check O2 coverage in your area, troubleshoot signal problems, set up WiFi Calling, and learn about 4G/5G coverage across the UK.

From our experience helping readers with coverage issues, here are the key steps to check your signal and troubleshoot any problems.

O2 Coverage Checker

Before signing up with O2 or if you are experiencing signal issues, you should check the coverage in your area using the official O2 coverage checker.

Check Coverage: Visit o2.co.uk/coveragechecker and enter your postcode or address to see the expected coverage levels for voice, 4G, and 5G.

Understanding Coverage Levels

The O2 coverage checker shows different levels of coverage:

  • Strong Outdoor Coverage: Good signal outdoors in most locations
  • Limited Outdoor Coverage: Signal may be patchy outdoors
  • Strong Indoor Coverage: Good signal indoors in most buildings
  • Limited Indoor Coverage: Signal may not work well inside buildings
  • No Coverage: O2 signal is not available in this area

4G Coverage

99% UK population

5G Coverage

450+ towns & cities

Voice Coverage

99%+ UK population

4G and 5G Coverage

O2 4G Coverage

O2's 4G network covers over 99% of the UK population outdoors. 4G provides fast mobile data speeds suitable for streaming, video calls, and browsing.

  • Typical 4G speeds: 20-50 Mbps
  • Available in most towns, cities, and major roads
  • Indoor coverage depends on building construction

O2 5G Coverage

O2 5G is available in over 450 towns and cities across the UK and continues to expand. 5G offers significantly faster speeds and lower latency than 4G.

  • Typical 5G speeds: 100-300 Mbps (can exceed 1 Gbps in ideal conditions)
  • Best for high-bandwidth activities like 4K streaming and gaming
  • Requires a 5G-compatible device and 5G-enabled plan

5G Ready: To use O2 5G, you need a 5G-compatible phone, a plan that includes 5G, and to be in a 5G coverage area. Check your device settings to ensure 5G is enabled.

WiFi Calling Setup

O2 WiFi Calling allows you to make and receive calls over WiFi when mobile signal is weak. This is particularly useful indoors or in rural areas.

Free to Use: O2 WiFi Calling is free for Pay Monthly and Pay As You Go customers. Calls made over WiFi use your standard plan allowances.

In our experience: WiFi Calling makes a huge difference in homes with thick walls or poor mobile coverage. Readers often tell us it's transformed their ability to make calls at home.

Setting Up WiFi Calling on iPhone

  1. Go to Settings > Phone (or Mobile)
  2. Tap WiFi Calling
  3. Toggle on WiFi Calling on This iPhone
  4. Enter or confirm your address for emergency services
  5. Connect to WiFi and you are ready to go

Setting Up WiFi Calling on Android

  1. Go to Settings > Connections or Network & Internet
  2. Tap WiFi Calling or Advanced Calling
  3. Toggle WiFi Calling on
  4. Follow any prompts to complete setup
  5. Connect to WiFi to use the feature

Compatible Devices

Most modern smartphones support O2 WiFi Calling, including:

  • iPhone 6 and newer
  • Samsung Galaxy S8 and newer
  • Google Pixel phones
  • Most recent Android devices from major manufacturers

Important: Your phone must be unlocked or locked to O2 to use WiFi Calling. If you brought your phone from another network, ensure it is unlocked.

Signal Boosters

If you have poor indoor signal, there are several options to improve your coverage:

WiFi Calling

The easiest solution if you have WiFi. Uses your home broadband to make calls and send texts. See the WiFi Calling section above for setup instructions.

Signal Boosters (Femtocells)

O2 previously offered signal boosters but has now phased these out in favour of WiFi Calling. If you have an existing O2 Booster Box, it should continue to work.

Third-Party Solutions

  • Passive Boosters: Window-mounted antennas that can improve indoor signal without power
  • Active Boosters: Amplify mobile signals but require Ofcom licensing in the UK

Legal Note: Using unlicensed mobile signal boosters is illegal in the UK. Only use Ofcom-approved devices. WiFi Calling is the recommended free alternative.

Tips to Improve Indoor Signal

  • Move closer to windows or external walls
  • Avoid basements and building centres
  • Enable WiFi Calling when on WiFi
  • Keep your phone software updated
  • Try removing your phone case temporarily

Quick tip from our team: Try switching your phone to airplane mode for 30 seconds, then back on. This forces a fresh connection to the network and often improves signal.

Reporting Outages

If you believe there is a network outage in your area, here is how to report it and stay informed:

Check for Known Outages

  1. Open the My O2 app
  2. Go to Network Status or Help section
  3. Enter your postcode to check for known issues
  4. You can also visit the O2 Status page online

Report an Outage

If there is no known outage but you are experiencing problems:

  1. Restart your phone and check if the issue persists
  2. Check your SIM card is inserted correctly
  3. Contact O2 via the My O2 app or call 202 from another phone
  4. Report the issue with your location details

Status Updates: For major outages, O2 will post updates on their website and social media channels. You can also check the O2 Status page at status.o2.co.uk.

What to Do During an Outage

  • Connect to WiFi and use WiFi Calling
  • Use messaging apps that work over WiFi (WhatsApp, iMessage, etc.)
  • For emergencies, all networks must allow 999 calls even without a signal from your usual provider
  • Wait for O2 to resolve the issue - most outages are fixed within hours

Signal & Coverage FAQs

Why is my O2 signal suddenly worse?
Sudden signal changes can be caused by network maintenance, new building construction, seasonal changes (trees in leaf block more signal), or issues with your phone. Try restarting your device, check for software updates, and use the O2 coverage checker to see if there are any known issues in your area.
How do I enable 5G on my phone?
On iPhone, go to Settings > Mobile Data > Mobile Data Options > Voice & Data and select 5G On or 5G Auto. On Android, go to Settings > Network & Internet > Mobile Network > Preferred network type and select 5G. Ensure you have a 5G-compatible plan and are in a 5G coverage area.
Does WiFi Calling use my data allowance?
No, WiFi Calling uses your WiFi connection, not mobile data. However, calls made via WiFi Calling count towards your plan's minutes allowance (or are charged at your standard rate if you have no minutes left). WiFi Calling does not use your mobile data allowance.
Can I use O2 signal if I have a phone from another network?
Yes, as long as your phone is unlocked, you can use it on the O2 network with an O2 SIM card. If your phone is locked to another network, you will need to contact that network to request an unlock before using O2.
Why do I have 4G signal but cannot make calls?
This can happen if VoLTE (Voice over LTE) is not enabled or supported. Try enabling VoLTE in your phone settings, or enable WiFi Calling as an alternative. If the problem persists, your SIM card may need replacing - contact O2 for a free replacement.

More O2 Signal Resources

If you continue to experience signal or coverage issues:

  • My O2 App: Check network status and report issues
  • Call 202: Free from your O2 mobile
  • O2 Coverage Checker: o2.co.uk/coveragechecker
  • O2 Status: Check for known outages at status.o2.co.uk

Sources & References

SM

Written by Sarah Mitchell

Mobile & Broadband Specialist

Sarah has over 8 years of experience helping UK consumers navigate mobile and broadband issues. Previously worked in telecommunications customer service and now writes guides to help others avoid common pitfalls.

Last reviewed: January 2026