Roaming Testing in Telecom: Ensuring Global Connectivity for Subscribers

With global travel and tourism at an all-time high, customers naturally expect their telecommunication services to work flawlessly, regardless of whether they’re outside the wireless provider’s coverage area.

Therefore, roaming isn’t a nice-to-have feature anymore; it’s a must for the everyday mobile experience. During the 2G and 3G eras, roaming charges regularly appeared as separate items on the customers’ phone bills.

However, that changed when nationwide and international plans came into play. Roaming testing gained precedence; it shifted from just a pre-deployment formality to a critical strategy for ensuring consistent service and accurate billing for the network provider and its subscribers.

In this blog post, we’ll discuss everything you need to know about roaming testing, including its core focus areas, standards and methodologies, and strategies.

What is Roaming Testing?

It refers to verifying the performance and functionality of a mobile phone’s ability to connect and use services, like data, voice, and SMS, across different networks, geographies, and sometimes entirely different rules.

When your subscribers leave your network and hop onto a roaming partner, they still expect everything to work: calls, texts, data, and even app notifications. They aren’t thinking about which network they’re on.

They’re only concerned with staying connected and monitoring the Quality of Service (QoS), and Quality of Experience (QoE) helps with that. That’s why testing in telecom is vital.

Core Focus Areas of Roaming Testing

This type of testing goes beyond signal strength. There are other essential factors to consider, including:

1. Billing accuracy

Errors in phone bills erode customer trust. Roaming testing equips you to check that:

• TAP (Transferred Account Procedures) files and BCE (Billing and Charging Evolution) flows are exchanged correctly

• Data usage is recorded the way it should be

• Discounts are applied properly

You get to protect your revenue and avoid customer complaints in one move.

2. Launch Readiness

Every new roaming agreement or product, like an eSIM or a new IoT use case, must be tested rigorously before it’s rolled out into the market. Roaming testing helps you meet technical standards, regulatory requirements, and customer expectations while reducing the risk of failure once you’re live.

3. Service availability

Can your subscribers make a call, send a text message, or use data when they land in another country? Roaming testing helps confirm that such services are available when and where they should be. You’re looking to catch gaps before they turn into support calls.

4. Service compatibility

Not all networks are built the same. Different technologies, configurations, or even regional restrictions can cause features to fail, sometimes silently. Roaming testing lets you identify mismatches between your services and your roaming partner’s setup. That means fewer surprises and more consistent experiences.

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Standards and Methodologies Applied in Roaming Testing

You don’t want to leave anything up to guesswork regarding roaming networks. That’s why it’s vital to follow well-defined standards defined by industry groups like 3GPP and GSMA to guide your testing efforts. There are two frameworks you should know about in roaming testing:

1. International Roaming Expert Group (IREG) testing

This ensures proper and reliable roaming services between two or more mobile network operators. IREG testing involves a series of standardized tests to verify their capabilities before they launch roaming agreements.

It helps verify that subscribers successfully register in a visited network and that various services, such as the following, function correctly:

• Can a call be placed and received reliably?

• Are SMS messages delivered without delay?

• Is data flowing at the expected speed for the network type (3G, 4G, 5G)?

• Do IoT devices connect and perform as expected, even with power-saving features?

2. Transferred Account Data Interchange Group (TADIG) testing

Introduced by the GSMA Working Group, this form of testing covers the billing aspect of roaming networks. TADIG tests ensure that call detail records (TAP files) and usage reports (BCE flow for IoT) are appropriately exchanged between roaming partners, keeping them aligned no matter where they operate.

Strategies for Effective Roaming Testing

If you’re already feeling the pressure from rising data demands, IoT expansion, or new products like eSIMs, follow these strategies to get ahead of the issues, strengthen partners, and keep your subscribers connected:

1. Choose between active and passive testing (or use both)

You’ll need to decide how hands-on your testing efforts will be. For instance, active testing involves simulating user behavior.

You place calls, send texts, use data, and monitor its performance in different roaming scenarios. You actively generate traffic to validate specific user cases.

Conversely, when you adopt the passive testing approach, you analyze real-world usage from actual subscribers. You collect Call Detail Records (CDRs) and QoS information from devices in the field and interpret them for trends or issues.

A hybrid model gives you control and precision along with context and scale.

2. Test with real devices in real-world conditions

Simulators can’t replicate roaming behavior in a synthetic environment. It’s a different ball game when a signal is technically life.

If you want to know how your service performs, test it under real conditions with real devices, including different locations, signal strengths, device types, and usage patterns.

Be sure to repeat tests over time, too—roaming conditions can change with network updates, seasons, or even time of day.

Also, roaming testing should be supplemented with user data to test signal strength, latency, throughput issues, and country-specific anomalies, such as time zone or daylight saving time (DST) misalignment.

3. Run regression testing for new releases

Each time you push a change, whether it’s to your core network, billing system, or device policy, roaming behavior shifts, too. That’s why it’s essential to run regression tests.

Set up baseline test cases for each roaming service. For instance, you can validate that data usage is metered correctly, calls are billed accurately, and fallback mechanisms (like switching from VoLTE to 3G) behave as expected. Repeat the tests every time you deploy a significant update.

4. Anticipate compatibility issues early

Before you begin to roam, ensure your home network is compatible with the partner work in the destination country and that there are no mismatched standards between networks.

You don’t want devices that can’t register, services that don’t behave the same way or partially supported features. Therefore, run end-to-end tests across your network and your partners’—don’t just assume things will “work out.”

In addition, keep an eye on firmware and device variations; what works on one handset model might not work the same on another, even within the same network.

5. Validate steering of roaming logic

To manage preferred partner networks, you must test your Steering or Roaming (SoR) logic carefully. Ask yourself:

• Are fallback options working if the preferred partner is down?

• Are your subscribers connecting to the right partner network upon arrival?

• Is your steering interfering with the user experience (e.g., delays, registration failures)?

Good SoR testing ensures you meet performance expectations and commercial agreements without compromise.

Roaming Testing in Telecom with TestGrid

TestGrid is an AI-powered end-to-end testing platform that can help you run real-world tests on actual iOS and Android smartphones and tablets under simulated network conditions, such as congestion, call quality, and even full-on 5G rollout scenarios.

You can run tests on devices dispersed across the US, India, and other global regions to see how your app behaves when the signal drops, multiple devices compete for bandwidth, or subscribers move between local and international networks.

Need to test on the newest hardware? Done. Want to see how your tech stack holds up under heavy usage or during a deployment cycle? Integrate TestGrid into your CI/CD pipelines to automate and keep the work efficient.

Benefit from robust reporting—replay live test sessions to pinpoint and troubleshoot performance issues that might go unnoticed. To explore its benefits yourself, start your free trial with TestGrid today.

→ Originally published on TestGrid.io blogs: Roaming Testing in Telecom.