A practical reference for UK mobile network identifiers, including current PLMN codes for the major operators, the Crown Dependencies, the Emergency Services Network, and how to use these codes when configuring a 4G or 5G cellular router.

Every mobile network in the world is identified by a six-digit Public Land Mobile Network (PLMN) code, made up of a three-digit Mobile Country Code (MCC) and a two- or three-digit Mobile Network Code (MNC). The UK uses MCC 234. Where a router status page shows a number like 23420 or 23415 instead of a friendly name, that number is the PLMN. Knowing what each code represents matters for roaming SIMs, multi-network deployments, and any situation where you need predictable behaviour from a cellular modem rather than letting it pick whatever signal is strongest.

What a PLMN Code Is

A PLMN code is the six-digit identifier your router uses to pinpoint a specific mobile network anywhere in the world. When a router scans for available cellular networks, it may return that six-digit number instead of a friendly name like EE or Vodafone.

The PLMN is built from two parts.

The Mobile Country Code (MCC) is a three-digit code assigned by the International Telecommunication Union (ITU) identifying the country. The UK MCC is 234. A secondary code, 235, is also allocated to the UK but rarely seen on consumer SIMs.

The Mobile Network Code (MNC) is a two- or three-digit code assigned by the national regulator (Ofcom in the UK) identifying the specific operator within that country.

Combined with no separator, the two form the PLMN. For example: MCC 234 plus MNC 30 equals PLMN 23430, which is EE. This is the value returned by the AT command AT+COPS? and the value entered when manually pinning a router to a specific network.

Current UK Mainland PLMN Codes

These are the codes most commonly seen on a router status page in 2026.

PLMN	Operator	Notes
23410	O2 (Virgin Media O2)	Telefónica UK Limited
23411	O2	Legacy O2 PLMN, still broadcast on some sites
23415	Vodafone UK	Part of VodafoneThree since May 2025
23420	Three UK	Hutchison 3G UK, part of VodafoneThree since May 2025
23430	EE	BT Group, primary EE PLMN
23431	EE	Legacy T-Mobile PLMN, still broadcast for backward compatibility
23433	EE	Legacy Orange UK PLMN, still broadcast for backward compatibility

The VodafoneThree merger completed on 31 May 2025, combining Vodafone UK and Three UK into a single business. The two physical networks and both PLMN codes (23415 and 23420) continue to operate during the integration period, and router scans will continue to see them as distinct networks for the foreseeable future.

Emergency Services Network (ESN)

The ESN appears in almost every UK network scan but cannot be used by commercial SIMs.

PLMN	Operator	Notes
23432	EE ESN	Emergency Services Network, visible to all devices but only ESN-issued SIMs can attach

The ESN is a dedicated LTE network operated by EE on behalf of the Home Office to replace the legacy Airwave TETRA service used by police, fire, and ambulance services. The PLMN 23432 is broadcast widely in router network scans, particularly in areas with extended rural coverage, but it cannot be used by commercial SIM cards. The MNC 32 was previously assigned to T-Mobile UK and was reallocated to the ESN after the EE merger.

Crown Dependencies (Channel Islands and Isle of Man)

The Crown Dependencies share MCC 234 with the UK because they sit under the same ITU allocation, but they are operationally separate networks. Their SIM cards are often issued as roaming or M2M SIMs used on the UK mainland.

PLMN	Operator	Territory
23450	JT (Jersey Telecom)	Jersey
23455	Sure (Guernsey)	Guernsey
23458	Manx Telecom	Isle of Man
23403	Airtel-Vodafone	Jersey and Guernsey (data-focused)

These codes are useful to recognise when running multi-network or steered roaming SIMs that attach to a Crown Dependency home network before roaming onto UK mainland infrastructure.

Historical and Legacy Codes

These codes still appear in older documentation or when comparing notes against pre-2010 router configurations. They are included here for reference.

PLMN	Original Operator	Current Status
23400	Virgin Mobile (legacy)	Withdrawn
23431	T-Mobile UK	Absorbed into EE
23432	T-Mobile UK / Virgin Mobile	Reallocated to EE ESN
23433	Orange UK	Absorbed into EE

The 2010 Orange UK and T-Mobile UK merger to form Everything Everywhere (later EE, now part of BT Group) is why multiple PLMNs still resolve to EE infrastructure.

How to Use These Codes in a Router

PLMN codes matter when running a roaming SIM, a multi-network IoT SIM, or any deployment where predictable behaviour matters more than letting the modem pick the strongest signal.

Manual Network Selection

In most cellular routers, including Teltonika RUT and RUTX devices, the mobile configuration page lets you switch from automatic to manual network selection. Entering the PLMN code pins the modem to that specific carrier. If the network is unavailable, the modem will not attach until it becomes available again, unless a fallback is also configured.

Preferred Network with Fallback

A more resilient approach for roaming SIMs is to set a preferred PLMN with automatic fallback enabled. The modem will attempt the preferred network first, and only attach to other available networks on the SIM's allowed list if the preferred one is unreachable. This is useful where one carrier offers better coverage, lower latency, or a more cost-effective data rate for a given deployment area.

Operator Scan Diagnostics

Running a network scan from the router returns a list of every PLMN the modem can detect, along with signal strength and the access technology (2G, 3G, LTE, NR). This is the most reliable way to confirm what is actually available at a site before committing to a SIM strategy.

Steered and Unsteered Roaming SIMs

Steered SIMs have a preferred network baked into their profile and will always try that operator first. Unsteered SIMs let the modem pick. Knowing the PLMN codes is what lets you verify which behaviour you are actually getting in the field. UK Roaming SIMs are the most common context where this distinction matters.

When You Might See an Unexpected PLMN

A few situations commonly produce surprises in a router scan.

Legacy EE codes (23431 and 23433) appearing alongside 23430. All three resolve to EE infrastructure.

PLMN 23432 in rural areas where ESN coverage has been extended. Visible to a router, but not attachable on a commercial SIM.

Crown Dependency codes when using certain M2M or roaming SIMs that have a JT, Sure, or Manx Telecom home network.

PLMN 23402 in parts of north Wales and other remote areas, associated with O2's satellite service launched in early 2026.

How Millbeck Supports Multi-Network and Roaming Deployments

Since 2002, Millbeck has been pairing cellular hardware with the right connectivity for the job. For multi-network and roaming deployments where PLMN behaviour matters, we supply multi-network IoT SIMs that can roam across UK and international operators, UK Roaming SIMs with predictable network selection, Global Roaming SIMs for international deployments, and cellular routers including the Teltonika RUT and RUTX ranges with full manual and preferred-PLMN configuration.

Whether a deployment needs a single-network SIM, a steered multi-network SIM, or fully unsteered roaming depends on use case, geography, and operating model. Talk to us about your project and we will help you decide.

Frequently Asked Questions

What Is the Difference Between MCC, MNC, and PLMN?

The MCC is the country code (234 for the UK). The MNC is the operator code within that country. The PLMN is the two combined into a single six-digit string. Routers and AT commands use the PLMN.

Why Does My Router Show a Number Instead of the Network Name?

Network name lookups depend on the modem's internal operator list, which may be out of date or missing entries for newer or specialised networks like the ESN. The PLMN is always returned even when a friendly name is not available.

Can I Force My Router to Use a Specific UK Network?

Yes. In most cellular routers you can set manual network selection and enter the PLMN code. If the SIM is not authorised to roam on that network, the modem will fail to attach.

Do Vodafone and Three Still Have Separate PLMN Codes After the Merger?

Yes. The merger completed on 31 May 2025, but the two physical networks (PLMN 23415 and 23420) continue to operate during a multi-year integration. Router scans will see both for the foreseeable future.

What Is PLMN 23432 and Can I Use It?

PLMN 23432 is the EE Emergency Services Network. It is broadcast widely so that ESN-certified devices can attach, but only Home Office-issued ESN SIMs can authenticate to it. A standard commercial SIM will see the network but cannot use it.

Are Jersey, Guernsey, and Isle of Man Codes the Same as UK Ones?

They share the UK MCC (234) but have their own MNCs and are operationally distinct networks. SIMs from these operators are sometimes used as roaming SIMs on the UK mainland.

What Is the Difference Between Steered and Unsteered Roaming SIMs?

Steered SIMs have a preferred network configured in their profile and will always try that operator first. Unsteered SIMs let the modem pick whichever available network gives the best signal. Both have their place: steered SIMs give predictable cost and performance, unsteered SIMs maximise resilience in mixed-coverage environments.