After more than two decades of dependable service, 2G and 3G mobile networks are now approaching their end-of-life across much of the world. With mobile operators reallocating spectrum to support high-capacity LTE and 5G networks, businesses still dependent on legacy connectivity risk service disruption—and potentially, critical system failure—if they fail to act.
This isn’t a routine technical upgrade. The 2G/3G sunset touches lifesaving services, IoT ecosystems, national infrastructure, and enterprise communication. While change is inevitable, those who plan ahead have an opportunity to futureproof their deployments, modernise operations, and gain access to a richer range of capabilities via LTE, VoLTE, and emerging 5G technologies.
This guide explains the drivers behind the shutdown, the technologies replacing legacy networks, and what businesses must do to adapt.
The Global Phase-Out: 2G and 3G Are Shutting Down—Fast
2G (GSM) and 3G (UMTS/HSPA) technologies have long served as the foundation of mobile communications, particularly in IoT deployments. However, their architecture is built on circuit-switched (CS) voice and low-rate data connections, neither of which meet the needs of today’s data-driven, real-time environment.
To free up spectrum and reduce infrastructure complexity, operators globally are retiring legacy radio networks. While the US was among the first to shut down both 2G and 3G, the pace is now accelerating rapidly across Europe, the Middle East, and Asia-Pacific. Industry forecasts suggest that by 2025, more than 200 network shutdowns will have occurred, including over 70 across EMEA alone.
This movement mirrors the wider retirement of the public switched telephone network (PSTN) in many countries—a full migration to IP-based voice and data.
IoT: The Sector Hit Hardest by the Sunset
While smartphone users may see only minimal disruption (such as limitations during roaming), the greatest disruption will hit the Internet of Things (IoT)—especially for long-life devices installed under the assumption of 10+ years of service.
Industries affected include:
- Elevator and lift communications
- Medical and fall-detection devices
- Emergency call systems
- Vehicle telematics and logistics
- Utility metering and smart grids
- Industrial monitoring and SCADA systems
Most of these deployments were built on the back of cheap, widespread 2G modules, chosen for their low power consumption and network availability. Now, these same devices face obsolescence.
Upgrading isn’t just about hardware replacement—it means choosing a new network technology, rethinking application design, and considering spectrum coverage, power consumption, and voice support in a completely new way.
Technology Alternatives: What Replaces 2G/3G?
There’s no one-size-fits-all replacement. Businesses must evaluate the right migration path based on use case, geographic coverage, and application requirements. Key options include:
📡 LTE Cat 1 & Cat 1 bis
- Ideal for voice and data applications
- Integrated into most LTE networks
- Cat 1 bis reduces cost and complexity by using a single antenna
🛰️ LTE-M (Cat-M1) and NB-IoT
- Suited for low-power, long-life IoT
- Embedded into 5G standards
- Not all networks support both; coverage varies
📞 VoLTE (Voice over LTE)
- Essential replacement for CS voice
- Enables voice as packet-based data
- Requires IMS-enabled devices and network support
🛜 Wi-Fi / Unlicensed LPWAN (e.g. LoRa)
- May be suitable for short-range or internal systems
- Not reliable for critical or voice-enabled applications
In most cases, LTE represents the most widely supported and flexible migration path. It integrates easily into operator networks, supports both voice and data, and will continue to be supported as a fallback technology well into the 5G era.
The Role of VoLTE: Beyond Voice
VoLTE is more than a voice replacement—it’s a vital enabler for the future of real-time communications.
Unlike 2G and 3G which relied on circuit switching, VoLTE transfers voice as data packets over LTE infrastructure. This not only improves clarity and call setup times, but also unlocks:
- IMS-enabled services (e.g., video calls, conferencing)
- Support for unified voice + data + diagnostics
- Consistent QoS (Quality of Service) controls
In fact, with the rise of 5G SA (Standalone), VoLTE is becoming the default fallback voice system for all 5G devices that do not support VoNR (Voice over New Radio). It’s estimated that nearly 5 billion VoLTE connections were active by the end of 2023, with growth expected to continue through 2025 and beyond.
SMS and PTT: Still Essential for IoT
IoT systems also rely heavily on SMS—for alerts, remote control commands, or provisioning—as well as Push-to-Talk (PTT) voice systems in logistics, security, and emergency scenarios.
But SMS over LTE is not the same as in 2G/3G:
- SGd messaging offers broad support across LTE networks and devices, requiring minimal changes
- SMS over IP is more futureproof but requires IMS capability, which not all devices or networks offer
PTT over LTE using VoLTE is now the best way forward. It ensures secure, independent emergency voice communications, even if power or network infrastructure is compromised.
In contrast, Wi-Fi-only systems rely on mains power and centralised architecture—making them unreliable in security-critical use cases.
In-Building and Private LTE Networks
The shift to LTE or 5G also opens up new connectivity strategies—especially for in-building enterprise use. More companies are adopting private cellular networks using LTE spectrum to:
- Deliver secure communications (e.g., lift phones, CCTV intercoms)
- Extend indoor coverage without relying on public networks
- Create isolated, self-managed IoT environments
Thanks to the emergence of Private LTE as-a-Service providers, enterprises can now deploy indoor coverage using licensed, shared, or unlicensed spectrum with minimal capital investment. Many are also turning to Fixed Wireless Access (FWA) solutions to provide backup broadband or dedicated channels for business-critical voice and data.
5G: Promise, Potential, and Limitations
With standalone 5G networks live in over 30 countries, some enterprises may consider skipping LTE entirely. However, 5G adoption for IoT remains limited by device cost, ecosystem maturity, and coverage.
Even so, forward-looking businesses may begin evaluating:
- 5G RedCap (Reduced Capability) for low/medium-bandwidth IoT
- 5G SA deployments using NB-IoT or LTE-M embedded in 5G architecture
- Fallback integration with LTE, essential for voice and roaming continuity
At present, LTE offers a far broader and more cost-effective ecosystem. It will also coexist with 5G for many years thanks to dynamic spectrum sharing, where LTE and 5G operate side-by-side within the same spectrum bands.
Strategic Considerations for Businesses
✅ Audit and Prioritise
Map out all devices using 2G/3G today, and prioritise replacements based on operational impact.
✅ Choose the Right Tech
Select technologies aligned with specific application needs: latency, power, coverage, and cost.
✅ Align with Network Plans
Check local operator shutdown schedules and evaluate LTE/VoLTE and NB-IoT/M1 coverage.
✅ Include VoLTE and IMS
Ensure your chosen hardware supports VoLTE and, where needed, IMS for future-proof messaging.
✅ Explore Private LTE
For large buildings, critical sites or remote deployments, consider deploying your own LTE core.
The Big Picture: Transition Now, Thrive Later
The 2G and 3G sunset isn’t a future event—it’s happening right now. For businesses relying on legacy networks, time is running out.
Yet within this challenge lies a significant opportunity: by modernising now, you unlock a future of richer services, enhanced reliability, and greater control over your connectivity.
LTE and VoLTE are the current champions, while 5G is fast emerging as the long-term foundation. What matters most is that you take the first step—now.
RoamingSIM: Your Partner in the 2G/3G Transition
At RoamingSIM, we provide:
- Multi-network IoT SIMs with LTE/VoLTE
- Private IP, Fixed IP and VPN support
- Future-ready 5G-compatible connectivity
- Consultancy to help you plan and migrate
Whether you’re managing 100 lift phones or 10,000 utility meters, we can help you switch smoothly and securely.
👉 Talk to us today at RoamingSIM.co.uk to get started.
