Call from any WiFi.
Anywhere in the world.
Telvio routes your calls over WiFi or mobile data instead of your carrier's network. No roaming plan. No international calling add-on. Just a working internet connection.
What is WiFi calling?
WiFi calling is a technology that routes voice calls over an internet connection instead of through your mobile carrier's cellular network. When you make a WiFi call with Telvio, your voice is converted into data packets, transmitted over WiFi or mobile data, and reconnected as a standard phone call on the other end.
The person you call doesn't need WiFi, an app, or any special setup. They answer their regular landline or mobile phone. From their perspective, it's a normal incoming call.
The practical result: you can call home from a hotel room in Tokyo, a cafe in Berlin, or an airport in Dubai — using the local WiFi — and pay Telvio's flat per-minute rate instead of your carrier's international roaming rate.
100 kbps
Minimum speed needed
Both upload and download
200+
Countries reachable
Landlines and mobiles
None
Carrier involvement
Bypasses your cellular network
$0
Roaming charges
Your carrier can't bill for it
How WiFi calling works
Connect to any network
Join any WiFi — hotel, home, cafe, airport. Or stay on mobile data. Telvio uses whichever internet connection your phone has.
Dial the number
Open Telvio and dial any real phone number with country code. The per-minute rate shows before you connect. No surprises.
They answer normally
Your call routes through a carrier-grade network. The recipient's phone rings like any other call. No apps, no internet required on their side.
Where WiFi calling works
Any location with a working internet connection. These are the most common ones.
WiFi calling vs roaming
Requirements
Internet connection
- WiFi — any network
- 4G or 5G mobile data
- Minimum 100 kbps both ways
iPhone requirements
- iOS 15.6 or later
- Any iPhone 6s or newer
- About 59 MB storage
Android requirements
- Android 7.0 (Nougat) or later
- Any Android phone or tablet
- Download size varies by device
WiFi calling questions
Does WiFi calling work on hotel WiFi?
Yes. Hotel WiFi works for Telvio calls as long as it has a stable connection with at least 100 kbps upload and download speed. Most hotel networks easily exceed this. If the connection is congested during peak hours, call quality may vary.
What internet speed do I need?
Telvio requires approximately 100 kbps in both directions for a clear call. That is much less than streaming video requires. Most WiFi networks, 4G, and 5G connections comfortably meet this threshold.
Does it work on mobile data, not just WiFi?
Yes. Telvio works over any internet connection — WiFi, 4G, or 5G. The term "WiFi calling" refers to the fact that you can call without using your carrier's cellular voice network at all, not that WiFi is the only option.
Will the call quality be worse than a regular phone call?
On a stable WiFi or 4G connection, call quality is comparable to a regular phone call. Telvio routes calls through Tier-1 carriers with professional-grade infrastructure. The person you call hears a normal phone call on their end.
Can I make WiFi calls while abroad to avoid roaming?
Yes, that is one of the primary use cases. Connect to any WiFi network abroad — hotel, cafe, airport — and call home at Telvio's flat per-minute rates. Your carrier's roaming charges do not apply because Telvio bypasses the cellular voice network entirely.
Which countries can I call using WiFi?
Telvio covers over 200 countries and territories. You can call landlines and mobile phones in the United States, United Kingdom, Germany, India, Canada, Australia, and many more. The person you call does not need WiFi or any app — they just answer their regular phone.
Call from anywhere. Pay per second.
Download Telvio and test with your included free minute. No roaming plan needed.
Download TelvioTwo different things are called WiFi calling
This is the single most common confusion in the category, and it costs people money because the two work in opposite ways.
Carrier WiFi calling is built into your phone by your mobile operator. It routes your normal calls over a WiFi network instead of the cell tower, keeps your own number, and consumes your existing plan. It is genuinely useful when the signal at home is poor. It is useless for cutting international costs, because the call is still billed under your carrier's tariff — including roaming rates when you are abroad, even though the call travelled over hotel WiFi.
A third-party VoIP app routes the call through its own network and bypasses the carrier entirely. The call is billed by the app at its own per-minute rate to the destination, and your carrier is not involved at all. That is where the saving comes from.
The practical test: if the call appears on your carrier bill, it was carrier WiFi calling. If it did not, it was VoIP.
What a call actually needs
| Bandwidth | Roughly 30–40 kbit/s in each direction, or about 15 MB for an hour. That is far less than any video stream and well within what a weak connection carries. |
|---|---|
| Latency | Under about 150 ms one way before conversation starts feeling like a radio interview. Satellite connections routinely exceed it, which is why calls on a plane or a ship feel wrong even when they work. |
| Jitter | Variation in packet arrival time. The buffer absorbs a little; beyond that, speech develops gaps. This is the usual culprit when a call is broken up on a connection whose speed test looks fine. |
| Packet loss | Above roughly 2% it is audible; above 5% the call becomes hard work. Congested shared networks — hotels, airports, student halls — lose packets in bursts rather than steadily, which is why they sound worse than their headline speed suggests. |
Making a WiFi call sound better
- Move closer to the access point. Signal strength affects retransmission, and retransmission is what turns into jitter. This is the single largest improvement available in most homes.
- Use 5 GHz where you can. Less congested than 2.4 GHz in almost every building, at the cost of range.
- Prefer a wired headset over Bluetooth. A Bluetooth headset switches to a low-bandwidth two-way profile the moment its microphone opens, which degrades audio in both directions. The same headset that sounds excellent playing music sounds like a telephone on a call, and that is the profile rather than the hardware.
- Try mobile data instead. On a congested hotel network, LTE is frequently the better connection for a call even though it is slower on paper.
- Check the microphone once. Level and echo problems are indistinguishable from network problems to the person listening. The microphone test separates them in ten seconds.
What WiFi calling cannot do
Reach emergency services reliably. An internet call has no fixed location, so an emergency operator cannot know where to send help. Every jurisdiction treats this differently and none of them treats it as solved; a phone arrangement needs a route to emergency services that does not depend on the internet.
Work without a connection. There is no fallback to the cellular voice network, by design — routing over the internet is what makes the call cost cents instead of dollars, and a silent fallback would produce exactly the surprise bill people are trying to avoid.
Guarantee quality end to end. The leg from your device to our network can carry wideband audio; the leg from our network to the recipient is limited by their operator's equipment. A call to a modern mobile network sounds noticeably better than a call to a legacy landline, and neither party can change that.
Bottom line
Carrier WiFi calling and a VoIP app are different products with the same name. The carrier version uses your plan and your number and still applies roaming rates abroad; a VoIP app bypasses the carrier and bills its own rate to the destination, which is where the saving is.
A voice call needs only 30–40 kbit/s each way and is far more sensitive to packet loss than to speed. On a congested hotel network, mobile data is often the better connection despite being slower on paper.
Frequently asked questions
What is the difference between WiFi calling and VoIP?
Carrier WiFi calling routes your normal calls over WiFi but still bills them under your carrier's plan, including roaming rates abroad. A VoIP app bypasses the carrier entirely and charges its own rate to the destination. If the call appears on your carrier bill, it was the first kind.
Does WiFi calling save money abroad?
Carrier WiFi calling usually does not — roaming rates still apply in most agreements even though the call travelled over hotel WiFi. A third-party VoIP app does, because your carrier is not involved in the call at all.
How much data does a WiFi call use?
About 30–40 kilobits per second each way, or roughly 15 megabytes for an hour of talking. Bandwidth is almost never the constraint; packet loss and jitter are.
Why does my WiFi call break up when the speed test is fine?
Because voice is sensitive to packet loss and jitter rather than to throughput. Congested shared networks lose packets in bursts, which produces gaps in speech while a speed test still reports plenty of bandwidth.
Why does my Bluetooth headset sound bad on calls?
Opening the microphone forces the headset from a high-quality playback profile into a low-bandwidth two-way one, which degrades audio in both directions. It happens in every application that opens a microphone, and a wired headset avoids it entirely.
Can I call emergency services over WiFi calling?
Not reliably from a VoIP app, because an internet call carries no fixed location and an emergency operator cannot know where to send help. Keep a route to emergency services that does not depend on your internet connection.
