Why Almost Everywhere Isn’t Enough: The Real Lessons of VoLTE Roaming

Voice over LTE (VoLTE) was once billed as the future of roaming voice. By carrying calls over 4G LTE’s IP data channels instead of legacy 2G/3G circuits, operators expected lower costs, higher capacity, and HD-quality voice. It promised to simplify infrastructure and align with LTE and 5G’s all-IP design. On paper, VoLTE has lived up to the promise. Last year, 90% of smartphone shipments were VoLTE-enabled, and more than 120 countries offered VoLTE services.

The reality, however, is not so smooth. Coverage gaps, under-optimized network environments, and incompatible handsets, are just some of the issues that have cropped up. For example, when a Canadian carrier shut down 3G recently, older OnePlus devices lost all voice capability.

It is perhaps time to reframe the way we think of VoLTE. We need to think of it not as a final destination but as a bridge, or a stepping stone.

The Impact of VoLTE Roaming’s Uneven Coverage

Why do we say ”almost everywhere”? This is because the coverage of VoLTE is broad but uneven.

• Asia-Pacific leads the way with almost 40% of the global VoLTE subscriber base. Pioneers like Japan and South Korea implemented VoLTE roaming as early as 2015, but other regions lag. 
• Europe likewise has heavy VoLTE adoption, led by Germany, UK, France, with roughly 87% coverage in urban areas. The EU’s “Roam Like Home” scheme and strict regulations have pushed operators to upgrade and collaborate. 
• In North America, adoption has been reactive. The U.S leads the way, with Canada starting to catch up. 
• By contrast, the Middle East, Africa, and Latin American regions lag behind when it comes to deploying VoLTE, with exceptions to be found in the GCC countries.

Because VoLTE “almost” everywhere is an invisible network layer, problems only show up when it fails. A traveler may enjoy crisp HD voice in Japan then suddenly face silence in the Mexico. For MVNOs, this inconsistency translates directly into churn and support costs.

What MVNOs Can Learn

To protect voice roaming, MVNOs should measure success by real user experience instead of just coverage maps. Key lessons include:

• Assume VoLTE gaps will exist and design redundancy into the system. For example, provide automatic fallback to local profiles or roaming SIMs (via eSIM or multi-IMSI solutions) and enable Voice-over-WiFi (VoWiFi) as a backup.
• Focus on experience metrics like call setup success, emergency call reliability, and Mean Opinion Score (MOS) quality. Customers care most about “did my call go through and was it clear”, not whether the network is labeled 4G or 3G. Monitoring end-to-end quality is crucial.
• Think big picture. VoLTE roaming is necessary today, but it’s also part of a longer evolution towards eSIM-driven, 5G-ready connectivity with Voice over New Radio (VoNR).
• Design for user behavior. Today’s international travelers often default to data-based apps (WhatsApp, Teams, etc.) instead of cellular voice. In fact, roaming revenues have stalled precisely because “travelers have discovered a better way”, bypassing traditional roaming and switching to third-party solutions. MVNOs need to recognize that customers expect seamless connectivity rather than a specific “phone call protocol”. In practice, that means offering easy access to local data (via eSIM) or integrated Wi-Fi calling, so that a user can open any app and have their voice (or video chat) work without even thinking about the network.

Essentially: prepare for trouble and focus on delivering a great user experience that matches the way people behave. At Telna, we support this evolution by helping MVNOs deploy resilient VoLTE roaming today while laying the groundwork for VoNR tomorrow.

Building for a Software-Defined, eSIM-First Future

VoLTE has proved its worth, but it was always a transitional solution to VoNR in 5G. What its uneven rollout has demonstrated is that voice quality alone isn’t enough. Customers measure success in whether their connectivity works everywhere, every time. 

That’s where eSIM changes the game by giving MVNOs and their subscribers the flexibility to switch between networks, download local profiles and failover seamlessly when VoLTE coverage is missing. It ensures that when gaps occur, users don’t notice. 

It’s no surprise that eSIM adoption has exploded, with more than 200 carriers now offering it globally. Travel eSIM providers enable one-tap local data access in nearly every market, changing how users think about roaming altogether. Instead of manually swapping SIM cards or hopping from WiFi spot to WiFi spot, travelers can now enjoy a new standard for roaming: instant, frictionless, and reliable.

For MVNOs, the opportunity lies in building software-defined, eSIM-first models. That means combining IMS-based voice evolution (VoLTE today, VoNR tomorrow) with flexible network access. At Telna, we enable this through a single global agreement, policy-based routing, and multi-profile eSIM flexibility that ensures customers stay connected everywhere, every time.

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