T-Mobile has good coverage in Tijuana, and because of that, so does Google Project Fi (which is what I use).

You might call your carrier and ask them, but for me, the only difference between the US and Mexico is that my voice calls cost me a few cents per minute.  Given that I only use voice to contact an agency to give them a room number when I arrive, this is a non-issue for me.  Data cost & limits is identical to the states on my plan, and the data coverage there has been good for me everywhere from the Ticuan to sitting in HK.

Wi-Fi in Ticuan is generally good, but I've heard mixed reviews on HK/Cascades but I've never personally tried to use theirs.

I have AT&T and international roaming in Canada and Mexico is included on my plan. Reception is usually pretty decent in MOST places.

You can get by using wifi in hotels and public places, but don't bank on it. Can get very spotty, but it can work pretty well too, especially if you're trying to Uber or something.

Ticuan wifi is pretty good and I gotta say Cascadas wifi has been really good to me as well MOST of the time. I usually try to stay in the higher floor rooms where I can not only use their wifi but usually get better coverage with my cell phone as well.

Cascadas wifi has been good enough for me to do work, stream movies, etc. Again this is MOST of the time.

If you will pay roaming fees while in TJ depends on both who your carrier is and even more important what plan you have with your carrier.

I have a T-Mobile plan that eliminates roaming fees between the US and Mexico and have yet to find a place in northern Baja that it doesn't work.  (Since I live in Tijuana I've used it in more places than you can shake a stick at.)

In Mexico, Telcel is the largest carrier,  but I have a Movistar phone.  They have a contract plan that for 200 pesos a month provides users with unlimited calls and texts without roaming fees plus a little 4G LTE data (which I don't need as I get data in TJ via my T-Mobile phone).   I don't recommend contract plans for casual tourists, but Movistar offers good prepaid plans without roaming fees that will meet the needs of most tourists.  (Telcel changes its plans at the drop of a hat, so sometimes they have no roaming fees and other times they do.)

Q: Why do I have a Movistar phone if my T-Mobile works everywhere?
A:  Because many of my Mexican friends don't have free roaming and won't pay the fees needed to call a US number.  Plus I like to get border crossing information from Telnor and Telnor blocks US numbers.  (So I have an Sony Xperia dual sim phone and I am glad I do.)

FYI:  You can get an old fashioned talk and text phone for either Telcel or Mexico usually for under US $30.00.  You buy either in tons of places but there is both a Telcel and Movistar store on 5th between Revolucion and Consitution.

There is Telcel (Mexico) and Telcel USA.  Last month I saw a Telcel USA plan that for US $30.00 a month provides unlimited talk and text without roaming fees plus 1 GB 4G LTE data on either side of the border.  If you're looking for a "secret phone," a burner, etc. you might look at Telcel USA offerings.

-- Modified on 2/13/2017 12:56:34 AM

Verizon:  I initially notified them to enroll free, and  use phone as usual costing $2/day.