For years, legacy 2G and 3G networks served as the dependable safety net for international voice roaming. If a traveler’s phone couldn’t establish a high-speed data connection, the device would simply fall back to these older networks to place a standard circuit-switched call.
Those days are officially coming to an end. Mobile network operators (MNOs) around the globe are aggressively shutting down legacy networks to free up valuable spectrum for 5G. But this shift has created an immediate, high-stakes challenge. Without 3G to fall back on, travelers roaming into regions where these networks have been retired will experience total silence — losing the ability to make or receive voice calls entirely.
Because of this, implementing Voice over LTE (VoLTE) roaming has quickly shifted from a "nice-to-have" upgrade to a critical business survival strategy.
Why VoLTE Roaming is Vital for MNOs
As the industry pivots toward an all-IP future, VoLTE roaming serves as the bridge keeping global voice communications alive. Beyond just maintaining basic call connectivity, VoLTE allows operators to deliver the modern, premium experiences that users now expect.
By launching VoLTE roaming, operators can:
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Offer crystal-clear HD voice and faster call setup times to roaming subscribers who expect premium services abroad.
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Capitalize on lucrative inbound roaming traffic and build stronger relationships with international partners.
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Utilize spectrum far more efficiently than legacy voice solutions, clearing the path for 4G and 5G expansion.
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Prepare the core network architecture to seamlessly support next-generation services, like 5G standalone (SA) voice.
Leading market intelligence firms have highlighted how rapidly this transition is taking place. According to Juniper Research, "Global wholesale roaming revenue is projected to double from $9 billion in 2024 to $20 billion by 2028. VoLTE roaming implementation is a core prerequisite to maintaining voice revenue as 2G/3G legacy networks disappear."1
The Real Roadblock: The Critical Need for Roaming Testing
While the benefits of VoLTE roaming are clear, actually turning it on is a complex technical challenge. Because VoLTE relies on the IP Multimedia Subsystem (IMS) core, establishing a functional roaming connection isn't a simple "plug-and-play" scenario. Every operator interprets standards slightly differently, meaning compatibility issues are incredibly common.
To ensure calls successfully connect, sound clear, and bill correctly, MNOs must execute rigorous testing. This includes:
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IREG (GSMA IR.25) Testing: Verifying that core services like voice, SMS, and emergency calls function flawlessly when transitioning between networks.
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TADIG Testing: Validating billing systems to ensure roaming partners can accurately exchange data and bill each other without revenue loss.
Without comprehensive testing, operators risk major service outages, poor call quality, billing disputes, and frustrated customers.
How Syniverse Simplifies the Journey and Lowers Costs
Faced with tight timelines, operators often lack internal resources, specialized training, and budget to handle this massive influx of testing. That is where partnering with a specialized expert like Syniverse makes all the difference.
As "the world's most connected company®," Syniverse offers a comprehensive, managed VoLTE roaming testing solution designed to alleviate these operational headaches:
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No new headcount: Syniverse's dedicated testing team removes the need to hire or maintain an expensive in-house testing function.
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No retraining: VoLTE testing is structurally different from legacy voice testing. Syniverse's specialists absorb that learning curve, so your existing teams don't spend months getting up to speed.
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Faster time to market: thanks to an extensive, proprietary troubleshooting database built from thousands of launches, Syniverse bypasses the usual trial-and-error phase. While standard testing cycles can drag on for months, Syniverse's testing cycles average around two weeks to complete a launch.
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End-to-end management: Syniverse handles everything from network provisioning and SIM management to partner coordination and final commercial launch signoffs, freeing up internal teams to focus on core operations.
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Proven scale: with over 900 successful VoLTE launches, more than 15,000 tests conducted monthly, and coverage across the globe, Syniverse has the proven blueprint to scale your roaming footprint seamlessly.
Don't Let Legacy Sunsets Silence Your Subscribers
As older networks continue to disappear, the clock is ticking for MNOs to establish secure, high-quality VoLTE roaming relationships. Partnering with the right expert ensures your subscribers stay connected with flawless voice quality, wherever their travels take them.
Ready to simplify your testing, protect your roaming revenue, and accelerate your path to the 5G future?
Discover how our team can help you today. Visit Syniverse Professional Services for Mobility to learn more about our complete suite of global roaming and connectivity services.
1.Juniper Research. January 2025. Global Wholesale Roaming Revenue to Double by 2028.
