hardware

5G Standalone in the UK: What It Means for IoT Routers, M2M SIMs, and Roaming Connectivity

17th February 2026 · 21 min read
5G IoT router supporting 5G SA, NSA, and 4G networks for seamless M2M communication.

A practical guide for anyone deploying or managing cellular routers and IoT devices in the UK’s rapidly evolving 5G landscape.

The UK’s mobile networks are in the middle of a fundamental shift. Three of the four major operators have now launched 5G Standalone networks, and coverage is expanding fast. For consumers with the latest smartphones, this mostly happens invisibly. For anyone deploying industrial routers, CCTV systems, or IoT devices with cellular SIMs, the picture is very different – and much more complicated.

This guide explains what 5G Standalone actually is, where the UK networks stand today, and why your 5G router might be stuck on 4G even when it can clearly see a 5G signal. More importantly, it tells you how to diagnose the problem and what to ask your SIM provider.

What Is 5G Standalone and How Is It Different?

To understand why 5G Standalone matters, you need to understand how the first wave of 5G was built.

5G NSA (Non-Standalone)

When 5G first launched in the UK, every network deployed it as Non-Standalone. This means the 5G radio (known as 5G NR – New Radio) was bolted on top of the existing 4G LTE infrastructure. The 4G network handled all the signalling and control functions, while 5G NR provided the faster data pipe.

In practice, your device connects to 4G first. That 4G connection acts as an anchor. Once the anchor is established, the device adds a secondary 5G NR carrier on top for additional speed. This is called EN-DC (E-UTRA New Radio Dual Connectivity).

The key point: 5G NSA requires a working 4G connection first. Without the 4G anchor, there is no 5G.

5G SA (Standalone)

5G Standalone removes the 4G dependency entirely. The device connects directly to a 5G core network using 5G NR for both signalling and data. No 4G anchor is needed.

This is not just a speed upgrade. It is a fundamentally different network architecture that enables:

  • Lower latency – no round-trip through the 4G control plane
  • Network slicing – dedicated virtual networks for specific applications
  • Better energy efficiency – devices do not need to maintain two radio connections simultaneously
  • Improved IoT support – the 5G core is designed from the ground up for massive device connectivity
  • Better coverage behaviour – the device connects to one network cleanly rather than trying to coordinate two

For IoT and M2M deployments, the most relevant benefit is reliability. A single, clean 5G connection is inherently more stable than a dual-connectivity setup that depends on both 4G and 5G being available and coordinated.

The Branding Confusion

Each UK operator uses different marketing terms for what is essentially the same technology:

  • EE calls it 5G+ (previously 5G Standalone)
  • Vodafone calls it 5G Ultra
  • O2 simply calls it 5G Standalone
  • Three – currently rolling out under the VodafoneThree merger, no separate consumer branding yet

If you see 5G+, 5G Ultra, or 5G SA on a coverage checker, they all mean the same thing: a pure end-to-end 5G network with no 4G dependency.

UK 5G SA Rollout – Where Are We in 2026?

The rollout has accelerated significantly over the past 12 months. Here is where each operator stands.

EE (BT Group)

  • Launched: September 2024
  • Current coverage: 66% of the UK population (approximately 44 million people)
  • Target: 99% population coverage by 2030
  • Key detail: EE only announces 5G SA in a location once it has at least 95% outdoor coverage there, so listed locations should offer a reliable experience
  • Notable: First European operator to deploy Advanced RAN Coordination (ARC) technology, and first to bring 5G SA to Wembley Stadium
  • Available on: All new and upgrading pay monthly handset plans at no extra cost. Also available on 5GEE Wi-Fi and 5GEE Home devices

O2 (Virgin Media O2)

  • Launched: February 2024
  • Current coverage: 500+ towns and cities, covering 70%+ of the UK population (approximately 49 million people)
  • Target: Continuing expansion as part of £700m Mobile Transformation Plan
  • Key detail: Claims the UK’s largest 5G SA deployment by number of locations. At least 90% outdoor coverage in each listed location
  • Notable: First UK operator to deploy 5G SA small cells (November 2024, Birmingham). Acquired 78.8 MHz of spectrum from Vodafone to support expansion
  • Available on: All O2 customers with a compatible device and SIM at no extra cost

VodafoneThree (Vodafone + Three UK)

  • Merger completed: May 2025
  • Background: Vodafone was the first UK operator to launch 5G SA in 2023. Three had paused its own 5G expansion in late 2022 due to costs
  • Baseline at merger: 47% population coverage with 5G SA
  • Target: 99% population coverage by 2030, 99.95% by 2034
  • Investment: £11 billion over 10 years, £1.3 billion in year one
  • Key detail: Currently rolling out MOCN (Multi-Operator Core Network) to let Vodafone and Three customers roam on each other’s networks. 500 MOCN sites live by August 2025, with 10,000 more targeted by March 2026
  • Notable: Vodafone customers have seen a 92% increase in 5G coverage experience since the merger began integrating networks

The Big Picture

By late 2025, a significant majority of the UK population had access to at least one 5G SA network, with most urban areas covered by two or three operators. The government’s Wireless Infrastructure Strategy calls for all populated areas to be covered by 5G SA by 2030.

This is important context for IoT deployments. 5G SA is no longer a future technology – it is live, expanding rapidly, and increasingly becoming the default 5G experience in the UK. Any IoT connectivity strategy that ignores 5G SA is already falling behind.

Why Your 5G Router Can See 5G But Cannot Connect

This is the scenario that catches people out constantly. A customer has a 5G industrial router – a Teltonika RUTX50, a Peplink, a Cradlepoint – with a roaming IoT SIM. The router’s network scan shows 5G cells clearly visible. Their iPhone, sitting next to the router, is happily connected to 5G. But the router stubbornly sits on 4G, often at disappointing speeds.

They try forcing the router to 5G-only mode. It either fails to connect at all, or briefly registers and then drops back.

This is almost never a hardware fault. Here is what is actually happening.

Seeing a Signal Is Not the Same as Being Allowed to Use It

When a cellular modem performs a network scan, it listens for broadcast signals from nearby cell towers. Each tower broadcasts its identity – a PLMN (Public Land Mobile Network) code consisting of a Mobile Country Code and Mobile Network Code – along with information about the frequencies and technologies it supports.

The modem can detect any signal that its radio hardware supports. A 5G-capable modem will see 5G cells regardless of whether the SIM inside it is authorised to use them.

Seeing the signal is step one. Registration is step two, and that is where things break down.

The Registration Process

When the modem attempts to register on a network, several things must happen:

  1. The SIM must authenticate – the visited network and the SIM’s home network exchange cryptographic credentials to verify the SIM is legitimate
  2. The roaming agreement must permit it – the home network must have a commercial agreement with the visited network that covers the specific technology being requested (4G, 5G NSA, or 5G SA)
  3. The SIM profile must support it – the SIM’s own capabilities must match the requirements of the network technology (more on this below)
  4. A data session must be established – even after registration, the APN must be accepted and an IP address assigned

If any of these steps fails, the registration is rejected. The modem then moves on to try the next available network or technology.

Why the Phone Works But the Router Does Not

In the scenario above, the iPhone connects to 5G because:

  • It is using a direct consumer SIM from the network operator (EE, O2, Vodafone, or Three)
  • That SIM has a native relationship with the 5G SA core network – no roaming is involved
  • The SIM is almost certainly a recent R15-compliant USIM that supports the security requirements of 5G SA
  • Apple has worked directly with UK operators to ensure device and SIM compatibility

The router fails because:

  • It is using a roaming SIM from an IoT MVNO or aggregator
  • That SIM’s home network may not have a 5G SA roaming agreement with the visited network
  • The SIM may be an older USIM profile that does not support the cryptographic requirements of 5G SA
  • The router’s modem firmware may need specific carrier configuration for SA operation on that network

The 5G signal is physically identical. The authorisation path is completely different.

The SIM Card Problem Nobody Talks About

One of the least discussed aspects of 5G Standalone is that it requires a specific type of SIM card.

The R15 USIM Requirement

5G SA networks are built on 3GPP Release 15 (and later Release 16) specifications. These specifications introduced new security requirements that older SIM cards simply cannot meet.

The most significant is SUCI (Subscription Concealed Identifier). In previous network generations, when a device registered on a network, it transmitted its IMSI (International Mobile Subscriber Identity) in the clear. This was a known security weakness that enabled IMSI catchers and location tracking.

5G SA fixes this by encrypting the IMSI before transmission, creating a SUCI. This encryption requires:

  • The SIM to store the home network’s public key
  • The SIM (or device) to perform elliptic curve cryptography to encrypt the subscriber identity
  • The SIM to support the 5G authentication framework (5G-AKA)

Only SIM cards manufactured to the R15 (or later) USIM specification support these features. An older 4G-era SIM card – even one that works perfectly on 5G NSA – will not work on 5G SA.

What This Means for IoT SIMs

Consumer operators handle this transparently. When you upgrade your phone or take out a new plan, you get an R15 SIM. EE, O2, and Vodafone have all been quietly replacing SIMs through their upgrade cycles.

IoT and M2M SIMs are a different story. Many IoT SIM providers are still issuing SIMs on older USIM profiles. Their platforms and roaming agreements were built around 4G, and the upgrade to R15 involves changes at the SIM manufacturing, provisioning, and network core level.

If your IoT SIM was issued more than two years ago, there is a reasonable chance it is not R15 compliant. Even some SIMs issued more recently may not be, depending on the provider.

5G SA and Roaming SIMs – The Hidden Gap

This is where the problem becomes specific to IoT and M2M deployments, because roaming SIMs face an additional hurdle beyond the SIM card itself.

Roaming Agreements Are Technology-Specific

When an IoT SIM provider like Wireless Logic, Telia IoT, emnify, or any other aggregator sets up connectivity, they negotiate roaming agreements with mobile network operators. These agreements specify which technologies the roaming SIM is allowed to use on the visited network.

A roaming agreement that covers 4G does not automatically cover 5G. A roaming agreement that covers 5G NSA does not automatically cover 5G SA.

5G SA roaming requires:

  • A commercial agreement between the home network and the visited network that specifically includes 5G SA access
  • Technical interconnection between the home network’s core and the visited network’s 5G core (not just the 4G core)
  • SIM provisioning that supports the security requirements of the visited 5G SA network

As of early 2026, many IoT SIM providers have 5G NSA roaming agreements in place with UK operators, but 5G SA roaming agreements are still being rolled out. The situation is improving, but it is far from universal.

The Practical Impact

If your roaming SIM does not have a 5G SA agreement with the local operator:

  • Your router will see the 5G SA signal (the radio does not care about agreements)
  • Your router will attempt to register on 5G SA
  • The registration will be rejected by the network
  • The modem will fall back to 5G NSA (if available and agreed) or 4G
  • If you force the router to 5G-only mode and the only available 5G is SA, the router will have no connection at all

This is not a fault. It is the system working exactly as designed. The SIM is not authorised for that service.

The FPLMN Problem – When Failed Attempts Make Things Worse

There is a secondary issue that can turn a minor inconvenience into a persistent connectivity problem.

What Is the FPLMN List?

Every SIM card maintains a Forbidden PLMN (FPLMN) list. This is a dynamic list stored on the SIM that records networks where registration has been rejected.

The purpose is efficiency. If a network has already rejected the SIM, there is no point in trying again. The modem skips forbidden networks during future scans, which speeds up the connection process.

How 5G SA Creates FPLMN Entries

When a router with a roaming SIM attempts to register on a 5G SA network and gets rejected (because the roaming agreement does not cover 5G SA, or because the SIM is not R15 compliant), the modem may write that network’s PLMN code to the FPLMN list.

Here is the problem: the FPLMN entry does not distinguish between technologies. It blocks the entire PLMN – meaning the modem will now also skip that operator’s 4G and 5G NSA service.

In a multi-network roaming SIM scenario, this can cause the router to progressively block every available network after failed 5G SA attempts, eventually leaving it with no connectivity at all, or stuck on a weak alternative network.

How to Clear the FPLMN List

The FPLMN list can be cleared in several ways:

Power cycle with SIM removal: Remove the SIM, wait 30 seconds, reinsert it and power on the router. This forces the modem to re-read the SIM and often clears the cached FPLMN data.

AT commands (for Quectel modems – common in Teltonika routers):

AT+CRSM=214,28539,0,0,0,""

This writes an empty string to the FPLMN file on the SIM, effectively clearing it.

Router settings: Some routers (including Teltonika models) allow you to lock the modem to specific network modes. Setting the mode to “4G only” or “LTE only” prevents the modem from attempting 5G SA registration in the first place, which avoids FPLMN entries being created.

SIM provider tools: Some IoT SIM management platforms allow remote FPLMN clearing via OTA (Over-The-Air) commands. Check with your SIM provider.

How to Diagnose the Problem – A Step-by-Step Checklist

If your 5G router is not connecting to 5G, or is stuck on 4G with poor performance, work through this checklist.

Step 1: Confirm What the Router Can See

Access your router’s web interface and run a manual network scan. This will show all visible PLMNs with their technology type (LTE, NR, NR-SA). Note which networks are visible and what technologies they are broadcasting.

On Teltonika routers, this is under Network > Mobile > Network Operators > Scan.

Step 2: Check Your Current Connection

Look at the router’s mobile status page. Key information:

  • Network type: Is it showing LTE, NR-NSA, or NR-SA?
  • Band: Which frequency band is the modem using?
  • RSRP / RSRQ / SINR: What are the signal quality metrics?
  • Operator: Which network is the router actually registered on?

If the router is on 4G with decent signal metrics but you can see 5G in the scan, the problem is almost certainly authorisation, not coverage.

Step 3: Check Your Router’s Network Mode Setting

Most 5G routers have a network mode preference setting:

  • Auto – the router will try the best available technology
  • 5G preferred – 5G first, fall back to 4G
  • 5G only – 5G or nothing
  • 4G only – forces LTE

If you are troubleshooting, try 5G preferred first. If the router still sits on 4G, it confirms 5G registration is being rejected. Do not leave it on “5G only” unless you are certain the SIM supports 5G on the available network.

Step 4: Check the AT Command Output

For deeper diagnosis, you can send AT commands directly to the modem. On Teltonika routers, use Services > CLI or SSH access.

Check the serving cell information:

AT+QENG="servingcell"

This returns detailed information about the current connection, including whether NR5G-NSA or NR5G-SA is active.

Check the FPLMN list:

AT+CRSM=176,28539,0,0,12

This reads the FPLMN file from the SIM. If it contains entries, those PLMNs are being blocked.

Check the modem’s 5G SA capability:

AT+QNWPREFCFG="nr5g_disable_mode"

This shows whether SA, NSA, or both are enabled in the modem configuration.

Step 5: Check the SIM

Contact your SIM provider and ask these specific questions:

  1. Is this SIM R15 USIM compliant? If not, it cannot support 5G SA.
  2. Do your roaming agreements include 5G NR on [specific UK operator]? Name the operator whose 5G signal your router can see.
  3. Is 5G SA registration supported, or only NSA? Many agreements cover NSA but not yet SA.
  4. Which APN should I use for 5G access? Some providers require a different APN for 5G data sessions.
  5. Can you check if my SIM has any FPLMN entries or network restrictions? Some platforms can view this remotely.

Step 6: Test With a Different SIM

The single most effective diagnostic step is to insert a consumer SIM from the local operator into the router. If the router connects to 5G immediately, the problem is definitively with the roaming SIM’s authorisation, not the router hardware.

Even a pay-as-you-go SIM from EE, O2, or Vodafone will work for this test.

What to Ask Your SIM Provider

If you are procuring IoT SIMs for new 5G deployments, or reviewing your existing connectivity, these are the questions that matter.

Before You Buy

  • Do your SIMs support 3GPP Release 15 or later USIM profiles?
  • Which UK mobile networks are included in your 5G roaming agreements?
  • Do those agreements cover 5G SA, or only 5G NSA?
  • Is there a timeline for adding 5G SA roaming where it is not yet available?
  • Do you offer eUICC/eSIM with 5G SA-capable profiles?

For Existing Deployments

  • Can you confirm the USIM version on my active SIMs?
  • If my SIMs are not R15, is there a SIM swap or OTA upgrade path?
  • Can your platform show me which technology (4G, 5G NSA, 5G SA) my devices are actually using?
  • Can you remotely clear FPLMN entries on my SIMs?
  • Do you support network mode locking through your management portal?

For Troubleshooting

  • Can you check the signalling logs for my SIM to see if 5G registration attempts are being rejected, and why?
  • Is there a specific APN I should use for 5G access?
  • Are there any known issues with 5G registration on [specific operator] in [specific area]?

Router Compatibility – Does Your Hardware Support 5G SA?

Not all 5G routers support Standalone mode. Even those that do may require a firmware update to enable it.

Key Factors

Modem chipset: The modem inside the router determines what the hardware can support. Common chipsets in industrial routers:

  • Qualcomm X55 – supports 5G SA and NSA (found in earlier 5G routers)
  • Qualcomm X62 (Snapdragon) – supports 5G SA and NSA with improved efficiency
  • Qualcomm X65/X70 – latest generation, full SA/NSA support with carrier aggregation
  • Quectel RM500Q / RM520N – common modules in Teltonika and other industrial routers, both support SA

Firmware: Even with SA-capable hardware, the router firmware must have SA mode enabled. Some manufacturers ship with SA disabled by default and require a firmware update or configuration change.

Carrier configuration: Some modems require operator-specific configuration files to enable SA on particular networks. These are sometimes called “carrier policies” or “MBN files” and may need to be loaded manually.

Popular Industrial Routers – SA Support Status

Teltonika RUTX50 – Supports both 5G SA and NSA. Dual SIM. Full Teltonika RMS integration. One of the most widely deployed industrial 5G routers in the UK.

Teltonika RUTM50 / RUTM55 / RUTM56 – Newer models with SA support and eSIM/eUICC capability. The RUTM56 adds dual modem for redundancy.

Teltonika RUT976 – 5G RedCap router. Supports SA. Positioned for mid-tier IoT applications where full 5G speeds are not needed but SA architecture benefits are.

Peplink MAX BR1 Pro 5G – Supports SA and NSA. SpeedFusion bonding. Popular in mobile and transport applications.

Cradlepoint E3000 – Enterprise 5G router with SA support. NetCloud management platform.

Robustel R5020 – Industrial 5G router with SA support and proprietary Smart Roaming technology designed specifically to address roaming SIM network selection issues.

If your router is more than three years old, check with the manufacturer whether SA is supported and whether a firmware update is needed.

What Is Coming Next

The 5G SA landscape is evolving rapidly. Several developments will directly affect IoT and M2M deployments over the next 12 to 24 months.

Network Slicing for IoT

One of the flagship capabilities of 5G SA is network slicing – the ability to create dedicated virtual networks with guaranteed performance characteristics. For IoT, this means you could have a slice with guaranteed low latency for industrial control, or a slice with guaranteed bandwidth for CCTV, running over the same physical network as consumer traffic but completely isolated.

Network slicing requires 5G SA. It does not work on NSA. As operators build out their SA coverage and start offering commercial slicing products, this will become a significant differentiator for IoT deployments that need guaranteed performance.

eUICC and 5G SA Profile Switching

Embedded SIM (eUICC) technology allows a SIM profile to be changed remotely without physically swapping the SIM card. This is particularly relevant for 5G SA because:

  • If one operator’s 5G SA roaming agreement does not cover an area, the SIM can switch to a different operator profile that does
  • As operators roll out 5G SA to new areas, devices can be remotely re-provisioned to take advantage of new coverage
  • R15 USIM profiles can be loaded onto existing eUICC SIMs via OTA update, potentially avoiding physical SIM swaps across entire fleets

Teltonika’s newer routers (RUTM30, RUTM51, RUTM52, RUTM55, RUTM56) all support eUICC.

5G RedCap – The Sweet Spot for IoT

5G RedCap (Reduced Capability) is a new device category within 5G NR that targets IoT and mid-tier applications. It offers:

  • Lower modem complexity and cost than full 5G
  • Better battery life
  • Speeds of 100-200 Mbps (more than enough for most IoT applications)
  • Full 5G SA architecture support, including network slicing

RedCap sits between 4G LTE and full 5G in terms of both capability and cost. For many IoT deployments – smart meters, building management, fleet tracking, environmental monitoring – it offers the architectural benefits of 5G SA without the cost of a full 5G modem.

Teltonika’s RUT976 is one of the first industrial routers to support RedCap, and more will follow.

Practical Recommendations

Based on everything covered in this guide, here is what we would recommend for different deployment scenarios.

New Deployments in 2026

  • Specify 5G SA support as a requirement for any new router procurement
  • Insist on R15-compliant SIMs from your IoT SIM provider
  • Ask specifically about 5G SA roaming agreements with UK operators, not just “5G support”
  • Consider eUICC-capable routers and SIMs for future flexibility
  • If 5G SA is not immediately needed, still deploy SA-capable hardware to avoid a forklift upgrade later

Existing Deployments Experiencing Issues

  • Run through the diagnostic checklist above before assuming a hardware fault
  • Check and clear the FPLMN list as a first step
  • Test with a local consumer SIM to isolate whether the issue is the router or the SIM
  • Contact your SIM provider about SIM upgrades or replacements if your SIMs are not R15
  • Consider locking to 4G as a short-term fix if 5G SA is causing FPLMN problems but is not yet supported by your SIM

Planning for the Next 12-24 Months

  • Monitor your SIM provider’s 5G SA roaming rollout schedule
  • Evaluate network slicing potential for deployments that need guaranteed performance
  • Consider 5G RedCap for new IoT deployments where full 5G speeds are unnecessary
  • Review your antenna systems – 5G SA may use different bands to 4G, and antenna selection matters for performance

Summary

5G Standalone is not a future technology in the UK. It is live, expanding rapidly, and fundamentally changes how cellular connectivity works. For consumer smartphones, the transition is mostly invisible. For IoT routers, M2M devices, and anyone using roaming SIMs, it introduces new layers of complexity around SIM compatibility, roaming agreements, and network authorisation.

The good news is that these are solvable problems. Understanding the difference between seeing a 5G signal and being authorised to use it is the first step. Asking the right questions of your SIM provider is the second. Deploying the right hardware and configuration is the third.

The UK’s 5G SA networks will only grow from here. The IoT deployments that will perform best are the ones that plan for this now, rather than troubleshooting it later.

For technical support with 5G router deployments, IoT SIM selection, or connectivity troubleshooting, contact the team at IoTPortal.co.uk.