What is an APN? Access Point Names Explained
The Short Answer
An APN (Access Point Name) is an address that tells your mobile phone which gateway to use when connecting to the internet over a mobile network. Without a correct APN, your phone cannot access mobile data — it will show signal bars but fail to load any websites or apps. The APN is stored in your phone's settings and is specific to your mobile carrier.
Most of the time, your phone gets APN settings automatically when you insert a SIM card. But this automatic configuration can fail — particularly on budget phones, factory-reset devices, unlocked phones bought second-hand, or when you switch to a SIM-only plan. When that happens, you need to enter the APN settings manually, which is exactly what this site is for.
Why Do APNs Exist?
Mobile networks are complex systems that carry multiple types of traffic simultaneously: your web browsing, streaming, messaging apps, MMS picture messages, and internal carrier services all need to be routed differently. The APN acts as a named entry point that tells the network: "this type of traffic should go through this specific gateway, with these credentials."
Think of it like a post code for your internet traffic. Just as a post code routes a letter to the right sorting office, the APN routes your phone's data to the right server on your carrier's network. Different carriers use different APNs because each has its own infrastructure and routing requirements. Even two carriers that share the same underlying network (for example, giffgaff and O2 both run on O2's infrastructure) use different APNs because they operate their own data gateways.
When Do You Need to Change Your APN?
You'll need to enter or update APN settings in any of these situations:
After getting a new phone (especially unlocked or refurbished): Unlocked phones that weren't sold by your carrier may not have your carrier's APN pre-configured. This is particularly common with phones bought directly from manufacturers like Google (Pixel) or OnePlus, or devices bought second-hand.
After a factory reset: Resetting your phone to factory settings wipes your APN configuration. If your carrier doesn't push automatic settings when you reinsert the SIM, you'll need to re-enter them.
After switching carriers (keeping your number): When you port your number to a new carrier, you get a new SIM. Some phones hold onto the old APN and don't update automatically. Manually entering the new carrier's APN is often necessary.
After inserting a SIM into an older phone: Phones from 2015 or earlier sometimes don't receive OTA (over-the-air) APN configuration. Manual entry is often required for these devices.
When MMS stops working after a software update: Major Android or iOS updates occasionally reset APN settings, particularly the MMS-specific fields.
Data APN vs MMS APN — What's the Difference?
There are effectively two parts to a complete APN configuration: the data APN and the MMS APN. On many devices and carriers, these share the same APN name but have separate routing for MMS via specific fields.
The data APN (the main APN field) is what handles your regular mobile internet — browsing websites, using apps, streaming video. For example, EE's data APN is simply everywhere.
The MMS configuration adds three extra fields on top of the data APN: the MMSC (MMS Centre, a URL), the MMS Proxy (an IP address or hostname), and the MMS Port (a number). These three fields tell your phone where to send picture messages and how to route them. If your mobile internet works but you can't send or receive picture messages (MMS), the issue is almost always in these three fields.
Quick fix: If your mobile data works but MMS doesn't — check the MMSC, MMS Proxy, and MMS Port fields in your APN settings. These are the most commonly missed values.
What Does Each APN Field Mean?
When you open the APN settings on your Android phone, you'll see a form with multiple fields. Here's what each one does:
| Field | Required? | What it does |
|---|---|---|
| Name | Yes | A label for this APN entry — shown in your APN list. You can name it anything (e.g. "EE" or "My Data"). It has no technical effect. |
| APN | Yes | The actual Access Point Name used by the network to route your data. This is the most important field and must be entered exactly as specified by your carrier. |
| Proxy | Rarely | An HTTP proxy server. UK carriers almost never use this for data traffic — leave blank unless specifically instructed by your carrier. |
| Port | Rarely | The port for the HTTP proxy above. Leave blank if Proxy is blank. |
| Username | Sometimes | Authentication username for PAP/CHAP authentication. Required by O2, giffgaff, and Lycamobile. Leave blank for carriers that don't require it. |
| Password | Sometimes | Authentication password. Used alongside Username for PAP authentication on O2-based carriers. |
| Server | No | Rarely used in the UK. Leave blank unless your carrier specifically tells you otherwise. |
| MMSC | For MMS | The URL of the MMS message centre — the server that handles sending and receiving picture messages. Must be entered for MMS to work. |
| MMS Proxy | For MMS | The IP address or hostname that routes MMS traffic through the carrier's messaging gateway. |
| MMS Port | For MMS | The network port used by the MMS proxy — typically 8080 or 8799 for UK carriers. |
| MCC | Yes | Mobile Country Code. For the UK this is always 234. Never change this. |
| MNC | Yes | Mobile Network Code. Identifies the specific carrier (e.g. 30 = EE, 10 = O2, 15 = Vodafone, 20 = Three). Must match your carrier. |
| Authentication type | Sometimes | The authentication protocol — None, PAP, or CHAP. UK carriers either use None or PAP. Use PAP if your carrier provides a username/password. |
| APN type | Yes | Defines what this APN is used for. Setting it to default,supl,mms covers internet data, GPS assistance, and picture messaging. Use this for UK carriers unless otherwise specified. |
| APN Protocol | Yes | The IP version to use. IPv4/IPv6 works on all UK networks and is recommended. IPv6 only may cause issues on older devices. |
| APN Roaming Protocol | Varies | The IP version to use when roaming abroad. IPv4/IPv6 is the safest choice. |
| Bearer | No | Restricts the APN to specific network types (e.g. LTE only). Leave set to "Unspecified" to work on all network types. |
Understanding MCC and MNC
The MCC (Mobile Country Code) and MNC (Mobile Network Code) together uniquely identify a mobile network. Every UK network has a fixed MCC of 234 (this is the ITU-assigned code for the United Kingdom). The MNC then identifies the specific network operator within the UK:
MNC 10 = O2 UK (used by O2, giffgaff, Tesco Mobile, Sky Mobile, Lycamobile, Virgin Media O2). MNC 15 = Vodafone UK (used by Vodafone, Lebara, VOXI). MNC 20 = Three UK (used by Three, iD Mobile, SMARTY). MNC 30 = EE (used by EE, BT Mobile).
These codes are used by the phone to match an APN entry to the active network. If the MCC or MNC in an APN entry doesn't match the network the phone is connected to, the APN will be ignored — which is why it's crucial to enter the correct MNC for your carrier.
APN Settings for UK Carriers
Here are direct links to the APN settings for the most popular UK carriers. Each page has the correct values for both Android and iPhone, plus step-by-step setup instructions:
Does Changing APN Affect Calls or Texts?
No. Voice calls use a completely separate channel on the mobile network (the circuit-switched domain) and are entirely unaffected by APN settings. Standard SMS text messages (the kind charged per message or included in your plan) also operate independently of the APN.
The only services affected by APN settings are mobile data (internet) and MMS (picture messages and group messages sent via the MMS standard). You can safely change your APN settings without worrying about losing calls or texts.
What About iPhone APN Settings?
On iPhone, APN settings work slightly differently. Apple restricts direct access to APN settings on iPhones sold by UK carriers — in those cases, the carrier pushes settings automatically via a carrier configuration profile. However, iPhones sold unlocked (from Apple directly, or internationally) and iPhones on some MVNO plans don't receive these automatic settings.
To access APN settings on iPhone, go to Settings → Mobile Data → Mobile Data Network. If this option isn't visible, your carrier is managing settings automatically. If you need to enter settings manually, follow our iPhone-specific guide on each carrier's page. Note that iOS saves APN settings automatically when you navigate away — there's no save button.
Still Having Problems?
If you've entered the correct APN settings and mobile data still isn't working, the issue may not be the APN at all. Check our comprehensive APN troubleshooting guide which covers the eight most common causes of mobile data failure. For APN terminology you're not familiar with, the APN glossary explains every term in plain English.