UK UK APN HubPremium UK network settings Browse APN
Last updated:

Three Internet Not Working Fix Guide

Follow these steps in order to diagnose and fix Three mobile data problems on Android and iPhone.

📋 On this page

  1. Check for Outage
  2. Quick Fixes
  3. APN Settings Check
  4. Advanced Fixes
  5. FAQs

Step 1: Check for Three Outage

Before changing any settings, check whether Three is experiencing a network outage in your area. An outage is the most common reason for sudden data loss.

Check Three status: https://support.three.co.uk/SRVS/CGI-BIN/WEBCGI.EXE?serviceType=coverage

If there is a confirmed outage, no settings changes will help — wait for the network to recover and check the status page for updates.

Step 2: Quick Fixes

  1. Toggle Aeroplane Mode on for 30 seconds, then off. This forces your phone to reregister on Three's network.
  2. Restart your phone fully — a restart clears network caches and reapplies APN settings.
  3. Check Mobile Data is enabled: Settings › Mobile Data (iPhone) or Settings › Connections › Mobile Data (Android).
  4. Check Data Allowance: if you've used your monthly data allowance, mobile internet will stop. Check in the Three app.
  5. Remove and reinsert the SIM card — a dirty or unseated SIM can cause data to drop intermittently.

Step 3: Verify Three APN Settings

Incorrect APN settings are a very common cause of mobile data failure, especially after a factory reset or SIM change. Verify the following values are set exactly:

APN: three.co.uk
  1. Open Settings › Connections › Mobile Networks › Access Point Names (Android) or check Three APN Settings for exact values.
  2. Verify the APN reads three.co.uk exactly — no extra spaces, no http://, no typos.
  3. Check APN Type includes default and supl at minimum.
  4. Save, activate the profile, and restart your phone.

Step 4: Advanced Fixes

  1. Reset APN to default: On Android, in the APN list tap ⋮ › Reset to Default. On iPhone, Settings › General › Transfer or Reset iPhone › Reset Network Settings (note: this also removes saved Wi-Fi passwords).
  2. Check for carrier settings update: On iPhone, Settings › General › About. If an update is available, install it and restart.
  3. Update your phone's software — a pending OS update can occasionally cause APN issues.
  4. Try the SIM in another phone — if data works in a different device, the problem is software or settings on your original phone.
  5. Contact Three support: 333 (free from Three) or 0333 338 1001. They can check whether there is a network-level issue with your account or SIM.

Frequently Asked Questions — Three Internet Not Working

How do I fix Three mobile data not working?
Toggle Aeroplane Mode for 30 seconds. Check APN is three.co.uk with no username or password. Check Three's service status at three.co.uk.
What is the Three APN?
The Three APN is three.co.uk. No username or password is required — Three uses an open APN. MCC: 234, MNC: 20.
Is Three down right now?
Check three.co.uk or @ThreeUK on Twitter/X for outage information. Three publishes service status updates on its website and app.
Why is my Three data so slow?
Three's network may experience congestion in high-traffic areas. Check signal strength, verify you're connected to 4G/5G (not 3G), and consider toggling Aeroplane Mode to reregister on the strongest available frequency.
How do I reset Three APN settings?
On Android: Settings › Mobile Networks › APN › ⋮ › Reset to Default. On iPhone: Settings › General › Reset Network Settings.

← Back to Three APN Settings

Advertisement space — Replace with your AdSense code (ca-pub-XXXXXXXXXXXXXXXX)