Heh. movistar in San Diego!
 

I'm in the Point Loma district of San Diego, California on holiday this week and I was amused when one of my phones grabbed onto movistar. I thought perhaps it was an urban network but it's actually service from Tijuana, Baja California, Mexico that I'm getting.

Tijuana is only about 15 km away but still, I would expect the service to be unreceivable here. I certainly can't receive US coverage at any distance from the US-Canadian border, except in rural areas. San Diego-Tijuana has 6 million people, not exactly rural.

Anyway, trivial, but entertaining. I can add one more country to the list of ones I've been registered to on a cell phone (.ca, .us, .uk, .ch, .de, .at, .li and now .mx).

Jim

Here in Europe it's something quite normal at border places, no matter if it's an urbanized or rural area. Expecially when operators use 850/900 MHz networks, it's quite normal that they go beyond borders...

yes, and they even force this by putting huge towers close to the border to catch poor people getting on roaming unrecognized...

Except in rural areas where there is no coverage on the other side of the border, Canadian and US carriers certainly attenuate their signal as much as possible near the borders. I couldn't get reliable AT&T or T-Mobile coverage at a hotel on Front Street in Niagara-on-the-Lake, Ontario, only two blocks from the Niagara River, a couple of weeks ago. To get movistar here (indoors!) is astounding.

We live in San Diego and if we go hiking near the Light House in Point Loma we get a message on our Verizon phones that says "Welcome to Mexico" etc. We have to be careful if we make a call not to pay Mexico Roaming. Point Loma is pretty far from the border too.

Depending on your phone, you can set it to manual network selection, which will solve the problem (and create a new one, depending on the provider, as there'll be no national roaming either).

Isn't there zero danger of an inadvertent outgoing call, as the dialing codes are different in Mexico, and the standard 1+area code +7 digits would not go through?

You should always set up your numbers with the + sign, followed by country code and number so they will work anywhere (such as +12125551212 or +491722222222). It's true, by omitting the GSM-standard plus sign, they might not work in Mexico, but that's no guarantee they won't call something else instead.

Motel75:

You are probably correct. I never tried making a call when the phone roamed to Mexico. This area has a number of hiking trails and cliffs. My bigger fear was not being able to make a call in the US if we were inadvertently set to roaming. FYI, our carrier is Verizon.

I did state there was little danger of an inadvertent "outgoing call". An inbound roaming call is probably more likely.