Cellular IoT has relied on legacy technologies like 2G and 3G for many years. These networks once delivered broad coverage and low device costs, enabling early IoT adoption across industries. However, they lack the capacity, efficiency, and performance required for modern data demands, and they occupy valuable radio spectrum that operators now repurpose for LTE and 5G services. Transitioning away from 2G and 3G is no longer optional for organizations with distributed connected fleets; it is an urgent operational imperative.

By the end of this article, you will understand what the sunset means, where it’s already happened, what risks it creates for IoT deployments, and how to migrate in a structured, resilient way.

When IoT Outgrows Its Original Networks

2G and 3G networks were foundational to early cellular connectivity, supporting voice, SMS, and basic data services that enabled the first generation of IoT deployments. As IoT ecosystems evolved, the scale and performance demands of connected solutions increased significantly. Requirements for higher data volumes, dense device deployments, low latency, and improved power efficiency have pushed legacy cellular technologies beyond their practical limits.

To address these demands, mobile operators are reallocating radio spectrum to LTE (4G) and 5G networks, which offer higher throughput, greater capacity, and more efficient spectrum use. This transition enables advanced capabilities such as network slicing and edge computing, while simplifying network operations. As LTE and 5G coverage expand globally, older technologies that cannot support these capabilities are being phased out.

This process, known as network sunsetting, involves decommissioning 2G and 3G infrastructure and repurposing those frequency bands for newer networks. Over the next decade, operators will continue phased shutdowns as modern coverage becomes ubiquitous. For IoT deployments that still rely on legacy connectivity, the risk is straightforward: without proactive planning, devices can lose connectivity permanently as these networks are retired. As IoT ecosystems evolve and connectivity demands increase, understanding how IoT connectivity is evolving across technologies and standards becomes critical.

Who Has Already Shut Down 2G and 3G

Sunsetting is not hypothetical. Many markets have already completed significant phases of legacy network retirement, and others have firm timelines.

Here are notable examples where the transition has already occurred or is well underway:

• United States: Major operators completed 3G shutdowns by 2022 and retired most 2G services earlier, leaving modern LTE and 5G available for all cellular connectivity. 
• Japan: 3G services have been sunset and removed from service; LTE and 5G effectively replace remaining legacy support. 
• Singapore: 2G was fully decommissioned in 2017, with 3G removed by 2024, making 4G and 5G the only active networks. 
• Australia: Operators have shut down most 3G services; 2G retirements are largely complete, with LTE/5G delivering mainstream connectivity. 
• Europe: Many carriers have shut down 3G already, with 2G scheduled to phase out in most countries by the late 2020s and into the early 2030s under structured plans.

Real-World Example: Logistics and Asset Tracking

• Legacy 3G asset trackers lost connectivity after U.S. network shutdowns
• Fleet visibility gaps forced emergency device replacements
• LTE-migrated deployments remained operational without disruption

Outlook for 4G and LTE: While 4G LTE has become the de facto fallback for mainstream consumer and IoT traffic, it is expected to remain in service for at least the next decade, with decommissioning projected to begin only after the 2030s and extend through the 2040s in many markets. 

The Impact and Risks of 2G/3G Sunsetting on IoT

Legacy network shutdowns have a much broader impact than simply losing connectivity. The effects ripple across technical, financial, and operational domains.

Service Disruption

When legacy networks are decommissioned, devices that relied exclusively on them will stop transmitting or receiving data immediately, disrupting business processes that depend on remote connectivity.

These disruptions may go unnoticed at first, but in critical systems like medical telemetry, smart meters, or eCall/safety services, the consequences can be severe.

Real-World Example: Utilities and Smart Metering:

• 2G-connected smart meters stopped reporting usage data.
• Billing and regulatory reporting workflows were disrupted.
• Manual reads or early device replacement increased costs

Operational Inefficiency

Devices still hunting for obsolete networks may enter repeated connection attempts, causing rapid battery depletion. Equipment designed for long life becomes a maintenance liability.

Roaming Instability

Even if a local operator nominally supports 2G or 3G, roaming partners in neighboring regions may have already switched off those technologies. This is especially challenging for global logistics and fleet applications.

Compliance and Business Risk

Regulated industries often have connectivity mandates for safety and reporting. Legacy disconnection may result in non-compliance or legal exposure if the required machine data no longer transmits.

Financial Shock

Unplanned truck rolls, device retrofits, and emergency replacements translate into unexpected capital and labor costs at scale. Upgrading hardware in the field is significantly more expensive than planned migrations.

Understanding these risks helps organizations transition from reactive problem-solving to proactive planning.

The Migration Path: Choosing What Comes Next

Moving away from legacy networks does not mean abandoning cellular IoT. It means choosing technologies optimized for modern needs.

Here are the most relevant successor technologies:

LTE-M (Cat-M1)

A cellular IoT standard that stays within LTE infrastructure while optimizing for lower power consumption, mobility, and broader coverage than traditional LTE.

Best for: Mobile assets, fleet tracking, wearable devices
Key attributes: Supports handover and roaming, Voice over LTE capability, and extended coverage.

NB-IoT (Narrowband IoT)

A narrowband LPWAN technology designed to deliver ultra-low power connectivity for simple devices that transmit small amounts of data infrequently.

Best for: Smart metering, environmental sensors, fixed industrial telemetry
Key attributes: Deep indoor penetration, very low power draw, long battery life.

5G RedCap (Reduced Capability)

An emerging 5G profile that offers many next-generation benefits at lower complexity and cost than full 5G radios.

Best for: Industrial IoT, future-proof deployments
Key attributes: Long lifecycle support, improved latency and reliability, built-in LTE fallback in many implementations. 

Real-World Example: Mixed IoT Connectivity Strategy

• LTE-M is used for mobile and roaming IoT assets
• NB-IoT deployed for stationary, low-data sensors
• Mixed approach reduces cost and future network risk

Deploying a mix of technologies based on device behavior, data needs, and lifecycle expectations is the most resilient approach. For a more detailed comparison of IoT connectivity options, including NB-IoT and LTE-M, refer to the ultimate guide to every IoT connectivity type.

The Solution Layer: How to Navigate Sunsets Without Disruption

A structured migration strategy reduces risk and cost. Here’s a practical path:

Step 1: Baseline and Prioritize

Compile a complete inventory of devices still using 2G and 3G. Assess deployment regions against sunset timelines.

Step 2: Segment by Use Case

Map devices to the successor technology that best aligns with mobility, data needs, power requirements, and cost constraints.

Step 3: Avoid Single-Operator Lock-In

Design connectivity strategies that allow switching between operators or networks without hardware changes.

Step 4: Migrate as Operational Optimization

Use the sunset as an opportunity to rationalize plans, deactivate unused capacity, and harmonize billing across regions.

Step 5: Use Lifecycle Controls

Establish automated workflows for provisioning, decommissioning, and scaling connectivity to prevent future disruptions.

Spenza: The Bridge Over Troubled Networks

Executing the steps above at scale is operationally complex. This is where platforms like Spenza act as an enabling layer rather than a point solution.

1. Unified Connectivity Management

Spenza provides a single operational view across legacy (brownfield) and modern (greenfield) deployments, helping teams manage transitions without splitting workflows across multiple carrier portals.

2. eSIM / eUICC Readiness

By supporting eSIM-based connectivity, Spenza enables remote carrier and network switching, allowing hardware to outlast the network standards it was originally deployed on.

3. Operator-Neutral Control

Instead of tying IoT fleets to a single carrier’s roadmap, Spenza’s marketplace approach allows teams to adapt as regional sunsets evolve.

4. Proactive Visibility

Centralized usage, status, and lifecycle data help identify at-risk devices early, reducing emergency truck rolls and unplanned downtime.

Beyond the Sunset: Rethinking Connectivity Strategy

Legacy cellular connectivity may be disappearing, but the true impact of 2G and 3G sunsetting is organizational rather than technical. As networks are retired, they expose how deeply many IoT deployments remain tied to decisions made years ago, often without a clear plan for long-term evolution. What surfaces as a network shutdown is, in reality, a stress test of how connectivity has been governed, monitored, and maintained across the device lifecycle.

For organizations operating IoT at scale, this moment separates reactive response from strategic intent. Those that treat sunsetting as a last-minute problem often face rushed replacements, fragmented migrations, and rising operational overhead. Those who use it as a catalyst to rethink connectivity ownership, flexibility, and lifecycle management emerge better prepared, not only for the current transition but for future network shifts that are inevitable in a rapidly evolving cellular landscape.

Strategic questions for leadership:

• How many devices in our portfolio still rely on legacy connectivity?
• What is our migration timeline relative to local sunset plans?
• Are we architected for operator and network flexibility?
• How do we manage connectivity as a lifecycle, not a commodity?

Addressing these questions now reduces risk and positions your IoT deployments for sustainable growth.

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