Viber vs WhatsApp: Which App Is Better for International Calls?

Fact-checked by the SnapMessages editorial team

When comparing Viber vs WhatsApp for international calls, the right answer depends on one key variable: are you calling someone who also uses the app? WhatsApp’s 2 billion-plus monthly active users make free VoIP calls available to a far larger audience, while Viber’s paid Out calling feature fills the gap when the other person has no messaging app at all.

With international roaming costs still high and traditional carriers charging premium rates, both apps have become essential tools for global communication in 2025.

Which App Delivers Better Call Quality?

WhatsApp generally delivers more consistent call quality at scale, but Viber’s HD voice technology performs competitively on strong connections. Both apps use VoIP (Voice over Internet Protocol) to route calls over Wi-Fi or mobile data, bypassing traditional carrier networks entirely.

WhatsApp uses the OPUS audio codec, which is optimized for varying network conditions and adapts in real time to bandwidth drops. Viber also uses OPUS and adds its own network optimization layer, which the company claims reduces packet loss on unstable connections. In real-world tests across Southeast Asia and Europe, both apps perform comparably on LTE and Wi-Fi, though WhatsApp tends to recover faster from brief signal interruptions.

For video calls, WhatsApp supports up to 32 participants in a group video call, while Viber supports up to 20 participants. If you regularly run large international video meetings, WhatsApp holds a structural advantage.

How Much Do International Calls Cost on Each App?

App-to-app calls on both platforms are completely free, but the real differentiator is calling non-app users on landlines or mobile numbers. This is where Viber Out pulls ahead of WhatsApp’s current offering.

Viber Out vs WhatsApp Calling Rates

Viber Out lets users purchase credits and call any phone number worldwide, with rates starting as low as $0.01 per minute to select countries. The service supports over 100 countries and allows calls to both landlines and mobile numbers. WhatsApp, by contrast, does not currently offer a paid outbound calling feature to non-WhatsApp numbers — all WhatsApp calls require both parties to have the app installed.

For businesses, WhatsApp Business API offers outbound messaging and calling infrastructure, but this is an enterprise-tier product. Individual users who need to reach someone on a regular phone line will find Viber Out a more practical solution, as noted in PCMag’s Viber review.

Which App Is More Secure for International Calls?

Both Viber and WhatsApp apply end-to-end encryption (E2EE) to calls and messages by default, but their privacy architectures differ in important ways. Understanding those differences matters, especially for calls that cross international jurisdictions.

WhatsApp uses the open-source Signal Protocol for end-to-end encryption, which is widely regarded as the gold standard for secure messaging. Viber uses its own proprietary E2EE implementation. While Viber’s encryption is independently audited, the use of a proprietary protocol rather than an open-source standard makes it harder for independent researchers to verify. For a deeper look at how E2EE works in practice, see our guide on end-to-end encryption explained.

Data Collection and Metadata

WhatsApp is owned by Meta and shares metadata — including contact lists, usage frequency, and device identifiers — with Meta’s advertising ecosystem, even though call content is encrypted. Viber is owned by Rakuten and also collects metadata, though it does not feed data into a social advertising platform of WhatsApp’s scale.

If metadata privacy is a priority for international calls, neither app is fully private. Alternatives like Signal collect substantially less metadata. For users concerned about phone-level security, our breakdown of how to detect spyware on your phone is a useful companion read.

Which App Has Better Global Reach?

WhatsApp dominates on raw user volume, making it the more reliable choice when you don’t know which app your contact uses. Viber leads in specific regional markets where WhatsApp has lower penetration.

WhatsApp holds the top spot in over 100 countries, including most of Latin America, India, and Western Europe, according to Statista’s 2024 global messenger rankings. Viber is the dominant messaging app in countries including Ukraine, Greece, Serbia, and the Philippines, where it has built strong network density ahead of WhatsApp.

This regional dynamic is critical for the Viber vs WhatsApp decision. If you regularly call contacts in Eastern Europe or Southeast Asia, Viber may already have higher adoption in your specific market. For users who communicate across multiple regions, running both apps side by side is a practical solution. Our comparison of WhatsApp vs iMessage covers how to evaluate messaging apps by geographic user base.

WhatsApp is unavailable in China, and access in Iran is restricted, which limits its utility for calls to those markets. Viber has broader access in some restricted regions, though both apps face regulatory challenges in certain countries.

What Extra Features Matter for International Communication?

Beyond calls, both apps offer features that directly affect how useful they are for ongoing international communication. The differences are subtle but worth knowing.

Viber includes disappearing messages, a built-in sticker marketplace, and Communities — a broadcast-style channel feature that supports up to 1 billion members per community. WhatsApp introduced Channels in 2023 as a similar one-way broadcast tool. For personal international communication, neither feature is decisive, but for diaspora communities or international interest groups, they add utility.

Both apps support cross-platform messaging between iOS and Android without friction. If you want to understand how this works under the hood, our explainer on cross-platform messaging between iPhone and Android covers the technical details. WhatsApp also recently added message editing (up to 15 minutes after sending) and improved multi-device support, letting up to 4 linked devices stay active simultaneously.

Viber’s desktop app is a standalone download that works independently without requiring your phone to be on or connected — a practical advantage for users who prefer to take calls from a computer. WhatsApp’s desktop app now also supports independent operation following its multi-device update, closing this gap significantly. For users interested in how AI is shaping messaging tools like these, see our coverage of AI features inside messaging apps.

Frequently Asked Questions

Is Viber or WhatsApp better for calling landlines internationally?

Viber is better for calling landlines internationally. WhatsApp does not support calls to non-app users, while Viber Out allows calls to any mobile or landline number starting at $0.01 per minute across 100+ countries.

Does Viber vs WhatsApp matter if both parties have either app?

If both parties have the same app installed, the call quality is comparable on strong connections. WhatsApp has a larger user base, so there’s a higher probability your contact already uses it — meaning fewer steps to connect for the first time.

Which app uses less data on international calls?

Both apps use roughly 1 MB per minute for voice calls on standard quality settings. WhatsApp’s adaptive OPUS codec can reduce data consumption further on poor connections. Neither app has a clear, consistent advantage for data usage at comparable quality levels.

Is WhatsApp or Viber safer for private international calls?

Both apps encrypt call content end-to-end by default. WhatsApp uses the open-source Signal Protocol, which is more transparent. However, WhatsApp shares more metadata with Meta’s ecosystem, so neither app is ideal for maximum privacy — Signal is a stronger choice for that use case.

Can I use Viber or WhatsApp without a SIM card for international calls?

Yes. Both apps work on Wi-Fi without an active SIM card, as long as the account was verified with a phone number at setup. This makes both apps useful on tablets or secondary devices when traveling internationally.

Which app is better in countries where WhatsApp is blocked?

Viber may have broader availability in some restricted regions. However, both apps are subject to local government regulations, and neither guarantees access in countries like China. A VPN may be required regardless of which app you use.