Privacy Blog

"Friends don’t let friends get spied on.' – Richard Stallman, President of the Free Software Foundation and longtime advocate of privacy in technology.

What is Wi-Fi Calling and Why Would I Want It?

NOTE: This is an update to the information given in my earlier article, What is Wi-Fi Calling and Why Would I Want It? A lot has changed since I published the original article three years ago. In fact, today I am a bigger fan of wi-fi calling than ever before. It works well and I save more than $100 in monthly wired and cellular telephone charges as well.

Many people think that a cell phone can only be used on a cellular network. Not true!

In the earlier article, I described Google Fi’s cellular service and how it could make cell phone calls over several different cell phone networks as well as over wi-fi networks, even switching connections in the middle of a call, if necessary. I stated “Phones for Google Project Fi are all expensive (check the latest prices as they vary often), but they are all high-end phones with the latest technology. I am using a Nexus 6P phone with Google Project Fi and love it.”

NOTE: Google’s Project Fi is no longer an experimental project. Instead, it is now a standard product in the company’s catalog. Therefore, it is now simply called “Google Fi.”

When the article was first published, Nexus 5X and Nexus 6P phones were the only devices that worked on Google Fi. That has since changed significantly. Today, a number of Android cell phones work with Google Fi with cell phone purchase prices starting at $99 US and going up. To save even more money, you can trade in most older cell phones for a credit and 0% device financing is available on most any new Google Fi-compatible phone purchased directly from Google.

I now use a top-of-the-line Pixel 3 cell phone and love it. However, I have stayed with Google Fi as my service provider. It is cheap, it provides better coverage in areas that have poor coverage from any other single company’s wireless service, and Google Fi works in more than 200 countries without any roaming fees.

NOTE: The lack of roaming fees when overseas is important to me as I travel a lot. It may or may not be a significant advantage for you, depending upon your travel plans.

Google Fi is no longer the only company that offers dual-mode phones. Republic Wireless, T-Mobile, Sprint, AT&T and Verizon all now provide built-in wi-fi calling on some cell phones, although perhaps not on all cell phones offered by each company. The details of how each company’s service works will vary significantly so do some reading first before signing up for any one company’s service. I will describe Google Fi in detail as that is the service I have been using for several years and I am most familiar with it. However, other companies may vary in their services.

Perhaps the biggest advantage of all for dual mode phones is for anyone who has flakey or non-existent cellular coverage at home. Dual mode cell phones work well on both cellular and wi-fi connections and most of them will even switch back and forth in mid-call without the user even knowing that the connection has changed. If you already have a wi-fi router in your home, you can now enjoy high-quality, reliable wireless telephone conversations whenever you are at home. All this works equally well for both receiving calls and for initiating outgoing calls. Of course, the same will be true anywhere else you travel if you can log into a good quality wi-fi network, such as when at work, at school, in the doctor’s office, in a hotel in Shanghai, or elsewhere.

NOTE: With most wi-fi networks, you only have to log in once and future visits to that location will then automatically make wi-fi connections without user involvement. However, there are some exceptions on some wi-fi networks where you may have to log in during each visit.

Many people who previously had to use two phones (wired and cellular) because of flakey cellular coverage at home have now found the in-home coverage offered by dual mode cell phones is so good they can now cancel their (expensive) wired telephone service and rely on the dual mode cell phone alone. That’s what I do: I have one cell phone with one telephone number and I use it everywhere: at home, at the office, at the grocery store, in the library, and while walking the streets of Singapore. Using a dual mode cell phone on wi-fi networks can save you hundreds of dollars per year. The more time you normally spend on calls and data over a cellular network, the greater the savings.

Skype, WhatsApp, Facebook Messenger, Google Hangouts, and other products have allowed telephone calls over wi-fi (and wired) Internet connections for years. However, these are typically separate applications. They do not use the same phone service as your normal cell phone. That is, if anyone calls your cell phone number, you cannot answer the call with Skype, WhatsApp, Facebook Messenger, or Google Hangouts. Also, if you place a call with any of these services, the Caller ID shown to the other party on the call does not show your cell phone’s number.

Newer services change all this.

Google Fi, Republic Wireless, T-Mobile, Sprint, AT&T and Verizon now provide built-in wi-fi calling on some cell phones, although perhaps not on all the phones they offer. All of these have available apps that install in your cell phone (or may be pre-installed when you purchase the phone) that will automatically switch from a normal cellular connection to a wi-fi connection or back again whenever appropriate. The software in the cell phone selects the more appropriate network selection, such as the strongest network signal or the cheapest.

The connection may switch even in the middle of a call if one network connection becomes weak or disappears and another improves. The cell phone owner may not even be aware which network is being used during a particular call. The other party in the connection is never aware of which connection is being used. Caller ID, call forwarding, and all other normal cell phone services work as usual.

Emergency Calls

Placing emergency calls to 911 used to be a problem on dual mode phones. It would work if connected to a cellular network but not if the phone was connected to wi-fi. A new service called E911 (or Enhanced 911) has solved the problem. All cell phones have built-in GPS receivers that can determine the phone’s exact location, plus or minus a few feet. Whenever I dial 911 on my dual-mode cell phone, the E911 service determines my phone’s exact location and sends it along in the Caller ID information to the emergency operator.

I tested this a couple of years ago when I had to make an emergency call to 911. I was at home alone and had serious abdominal pains. The only phone I had was my dual mode cell phone operating on Google Fi’s network. I dialed 911 and an operator answered immediately. I briefly described the problem and asked for an ambulance. The operator never asked for my street address

About 5 minutes later, an ambulance and two first responder medics appeared in my driveway. Soon after, a large firetruck also arrived, along with several firemen. The firetruck was too large to fit in my driveway but was parked in the street in front of my house.

To make a long story short, I was soon transported to the hospital and a few hours later had an emergency appendectomy. Yes, I am a fan of E911!

Why would anyone want a dual mode phone? Many reasons:

1. If you are in a location that has weak cellular signals but a strong wi-fi signal from your in-home router, the use of a dual mode phone can provide better service and often saves money. You only need one phone: your cell phone. There is no need to have a second phone line provided by the local telephone company. For many people who live in an area with weak or nonexistent cell phone service but do have an Internet router with wi-fi, this can be a huge advantage.

2. If you are in a building or an area with weak cellular connections, a wi-fi connection can provide much more reliable phone service.

3. Use of a cell phone as your only telephone allows for text messaging all the time. (Normal telephones from the local telephone company do not have text messaging capabilities.)

4. You only have to give out one telephone number to friends, family, and business associates. You no longer have to tell people, “If you call between 8 AM and 5 PM, use this number but if you call on Thursday evenings, call this other number…”.

5. Wi-fi calling works from overseas locations, usually avoiding exorbitant roaming charges. Instead of having a $300 roaming charge after your overseas vacation, use of wi-fi connections will add zero or nearly zero charges to your monthly cell phone. However, be aware that a very few companies do charge extra for international calls, even over wi-fi. See each company’s web site for the details.

6. Even when traveling internationally, your friends, family, and business associates can still reach you by dialing your normal cell phone number. If you are connected to a wi-fi network at the moment they call, your phone rings immediately and you can answer exactly the same way as you would back home, even if you are in Tel Aviv. If you are not connected to either a wi-fi network or a cellular at the moment, the caller will be connected to your voice mail, and you can return the call later as you wish.

Before you can take advantage of these offerings, you must buy one of the dual mode phones and use it on a network that supports its capabilities: in the U.S., that includes Google Fi, Republic Wireless, T-Mobile, Sprint, AT&T or Verizon. Again, not all phones are dual mode, even those used on T-Mobile, Sprint, AT&T or Verizon.

Phones used on Google Fi are unlocked and can easily be switched to almost any other company’s service; so, if you do switch and then change your mind, you will not be left with an expensive and useless cell phone. On the other hand, phones designed for use on Republic Wireless are locked to that company’s service, so your initial purchase of the cell phone might be wasted if you later decide to switch to a different cell phone carrier.

If you are willing to pay higher prices, all four major US carriers (T-Mobile, Sprint, AT&T and Verizon) provide built-in wi-fi calling on some phones, but not on all. If you are presently locked into a contract with a major cell phone company, you might be able to switch to a dual mode phone from the same company without paying an exorbitant fee for early termination of your present contract. Note the use of the word “might” in that sentence; you will need to ask your carrier if they will allow such a change.

NOTE: Google Fi and Republic Wireless have no contracts so there are no termination fees. You can cancel at any time without paying any extra fees.

If your present cellular contract has already expired, you might want to switch to either Google Fi or one of the other companies that offer dual mode cell phone service. You can have your present phone number switched to the new phone.

Does it cost more?

For domestic calls within the US, use of a dual mode phone doesn’t cost any extra. On Google Fi and Republic Wireless, dual mode phones will probably save you money. In many cases, they will save a LOT of money.

Google Fi costs $20 a month for unlimited voice calls and unlimited text messages to and from US telephone numbers. In addition, data connections over wi-fi networks are free. Data connections over cell phone networks cost $10 per gigabyte for data, $20 for 2GB, $30 for 3GB and so on. Unused data connection fees are refunded on your next month’s bill. For instance, if you pay $10 a month for one gigabyte but this month you only use a half gigabyte, Google Fi will refund $5 on your next bill. Even better, once you hit 6GB the monthly price automatically caps at $80. After that you get unlimited high-speed data for free.

That’s it. With no annual contract required. Details may be found at

Republic Wireless has more complex pricing, ranging from $12.50 a month to $25 a month. Details may be found at

T-Mobile, Sprint, AT&T, and Verizon all have very complex prices, which makes it hard to compare “apples to apples” with the aforementioned two. There may or may not be monthly limits on your minutes allowance for voice calls or your gigabyte allowance for data. You often do not get a refund for unused minutes or data.

In addition, with T-Mobile, Sprint, AT&T, and Verizon, pricing often varies from one part of the country to another. For instance, monthly cell phone prices in New York City are almost always higher than in Orlando. T-Mobile, Sprint, AT&T, and Verizon all charge higher prices than either Google Fi or Republic Wireless. On T-Mobile, Sprint, AT&T, and Verizon, placing calls over wi-fi may or may not impact your regular minutes allowance, depending on your carrier and your phone plan. Be sure to read the policies of your carrier to see if any of their potential restrictions and charges relate to your situation.

Check each cellular company’s web site for the details.

To place calls to other countries, additional fees may be involved. However, calls placed with Google Fi are normally much, much cheaper than what your present cellular company charges for the same call. Switching to Google Fi for international calls can save a lot of money.

Republic Wireless only supports making calls to the United States, Canada, Puerto Rico, Guam, US Virgin Islands, American Samoa, Northern Mariana Islands, Johnston Atoll, Midway Atoll and Wake Island. However, calls to areas outside the 50 states, Canada, or the District of Columbia may be charged an extra 50 cents per minute.

Does it work overseas?

All dual mode phones will work overseas when connected to wi-fi. Depending upon the company that provides the dual-mode service, the cell phone may or may not work when walking down the street, not connected to a wi-fi network.

Google Fi works in more than 200 countries, and roaming charges in those countries are almost nonexistent. I have used Google Fi in the United States, Canada, Mexico, England, Scotland, Norway, Germany, Israel, New Zealand, Australia, Thailand, China, Taiwan, Bahamas, Grand Cayman Island, and in a few other places as well, all without any roaming fees.

When I used the same phone in Singapore for a week, I found a “roaming fee” of 35 cents US on my next month’s bill from Google. I can live with a 35-cent roaming fee for a week’s service. I placed and received a number of calls while in Singapore, including receiving calls while walking along the streets and using a local cellular network, not wi-fi.

If you are in a country not included in the list of 200 partner countries, normal roaming charges apply. Details may be found at

Do I need a fast wi-fi connection?

Though the higher throughput you have, the better your connection will be, a minimum of 1 megabit per second (Mbps) should be enough to provide high quality audio. Republic Wireless reports that it can hold a call with 80 kilobits per second, but the quality may decrease—and you’ll experience more dropped calls as well. Most dual mode phones will test the wi-fi network speed before establishing a connection. If the speed is too slow, most dual mode phones will not connect to the wi-fi network but then will use the local cellular network for calls.


One “problem” is that the user needs to manually establish a connection to a wi-fi network before it will be used for telephone calls. Most wi-fi networks in hotels, coffee shops, and elsewhere require the user to connect manually and then agree to the network’s terms of service. A user name and password are also sometimes required. A dual-mode cell phone cannot perform this for you automatically; you must do it yourself manually. Once connected, future connections to the same wi-fi network will usually be made automatically and invisibly. However, many hotels do require a new manual connection and agreement with the terms of service be made once a day.

If you have not previously connected to the wi-fi network manually, entered the user name and password, and agreed to the terms of service, that wi-fi connection cannot be used by the dual mode cell phone. The restriction is caused by the wi-fi network, not by the cell phone.

There is no such limitation when using a cellular connection; in that case the dual mode phone works in exactly the same manner as any other cell phone.


Use of a dual mode cell phone can provide better service for you and also save lots of money. Use of Google Fi or Republic Wireless will probably cut your present cellular bill dramatically. When traveling overseas, use of any dual mode phone on a local wi-fi network will avoid exorbitant roaming fees. In 200+ different countries, use of Google Fi or normal cellular networks will also avoid most roaming fees.

I previously used Republic Wireless for a couple of years, then switched, and now have used Google Fi for more than three years. The Republic Wireless phone did not work outside the United States. I have since used the Google Fi cell phone and have used it frequently during my international travels to make and receive calls. “It just works.” There are no hassles and no exorbitant roaming charges in the 200+ supported countries.

Before dual mode cell phones were available, my earlier cell phone provider charged more than $80 a month for normal cellular service within the US and added huge roaming charges when used outside the country, even when in Canada. In contrast, Google Fi costs $30 a month for unlimited voice minutes, unlimited text messages, and 1 gigabyte of data with more data available at low prices, should I need that. In return, I get better coverage, higher fidelity connections, and almost zero roaming fees when traveling.

More data is available for $10 per month per gigabyte, and any unused data gets refunded back to me. For example, if I only use 0.65 gigabytes of data in any month, I only pay $6.50 US for that month’s data usage.

I used to have marginal cell phone service in my home. If I was in the basement, the cell phone didn’t work at all because the nearest cell tower did not supply a strong signal to my basement. I also had an old-fashioned telephone line provided by the local telephone company that cost more than $30 a month plus toll charges. After using a dual mode cell phone for a few months, I had the old-fashioned phone line disconnected and I now use the cell phone as my only telephone. My in-home wi-fi network provides much better signals throughout my home, even in the basement, than did my previous cell phone provider. I no longer need a wired telephone line. My friends, relatives, and business acquaintances are now given one telephone number that will reach me 24 hours a day, 7 days a week, regardless if I am at home, at the office, in the automobile, or in Shanghai.

Thanks to the cheaper cell phone service and the elimination of my $30/month old-fashioned landline, I am now saving more than $100 a month.

I’m happy with my better and cheaper cell service.

How big is your present cellular and regular telephone bill?

Disclaimer: I am not compensated in any way for writing this article. I am simply a very satisfied customer of Google’s Fi. Previously, I was a customer of Republic Wireless although that company did not meet my needs when traveling internationally. When Google Fi became available, I switched to the new service and now I save even more money. If you do not travel internationally, Republic Wireless might be your better choice.

Categories: Cell Phones, Travel

1 reply

  1. I switched to Google Fi a few years ago when Dick Eastman first brought it to my attention (and when it was still labeled as Project Fi). I live in a very rural setting with mountains and valleys. None of the cellular networks provides 100% signal coverage, but Google Fi is as good as any of them, and at a much better price. When I am home, my Fi cell phone works over my WiFi router seamlessly, and the voice quality is equal to my home land line. When I am somewhere like a doctor’s office I usually have to sign in to that WiFi signal once. Then, on repeat visits, the phone logs in automatically without me even being aware of it happening.
    After several years of using Google Fi I cannot understand why anybody would use any other service. By the way – you have probably never seen an ad for Google Fi because it appears that they just don’t advertise their service. But that’s fine with me because it’s saving them money and it’s sort of like a private club.

    You should definitely give this a try. Because not every phone works with Fi, the best time to switch is when you are thinking about a new phone.
    The phones offered through the Fi service do seem to work the best.


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