Not all countries cost the same: the zone table that determines your roaming bill

There's a widespread and reasonable belief that a megabyte of data costs more or less the same everywhere, like electricity or water.

That's false. And the difference isn't ten or twenty percent. It's an entirely different order of magnitude.

What determines the cost of internet for a trip isn't how much you use your phone. It's which zone the destination country falls into according to your carrier's table. That table is published, you can consult it, and almost no one looks at it before buying a plane ticket.

How the zone system works

Mexican carriers group countries worldwide into categories. The names vary by company, but the logic is the same.

There's a large, predictable group where rates are reasonable: the United States, Canada, much of Western Europe, and much of Latin America. These are the destinations with the most traffic and where the carrier has better wholesale agreements.

And then there's everything else. This includes destinations that, for the Mexican traveler, are not at all exotic: parts of Asia, Africa, the Middle East, some Caribbean islands, and several Eastern European countries. For the user, they are normal tourist destinations. For the table, they are another category.

The underlying reason is that roaming originated as an agreement between carriers, not as a service designed for the customer. The price is set between companies that charge each other and pass the bill on to the traveler. That's why the numbers are so difficult to explain in terms of actual cost.

Published figures

Telcel's international roaming catalog includes products that are not at all alike:

• A 15 GB package valid for 20 days for the United States, Canada, Latin America, and Europe, for 949 pesos.
• A 100 MB package from the Preferred Countries B category, valid for 30 days, for 1,949 pesos.
• A 20 MB package from the Rest of the World category, valid for 30 days, for 6,000 pesos.
• For maritime navigation, a 1 MB package for 400 pesos.

Source: International roaming rates published by Telcel and registered in the Rate Book with the Federal Telecommunications Institute.

It's worth translating the last figure, because in the abstract, it means nothing. Twenty megabytes is less than a single photo taken with a modern phone. It's what a device might consume while sitting in a bag, syncing email and checking for updates.

The special case of cruises

This deserves separate mention because it surprises even experienced travelers.

When the ship is on the high seas, the phone doesn't connect to a land-based antenna. It connects to the ship's own satellite antenna, and that connection is charged differently and notably more expensively than normal land-based roaming.

Many people assume there's simply no signal at sea. There is, and the device connects to it if data roaming is active. This is one of the scenarios where the most involuntary consumption occurs, because the passenger is convinced they are disconnected.

Why no one tells you

This is the part that annoys those who experience it the most, and the explanation is quite prosaic.

The table is published, but it doesn't appear at any of the times when it would be useful. The travel agency doesn't mention it when selling a package. It doesn't appear during the flight purchase process. It doesn't come up when booking a hotel. And if you call the carrier to ask about something else, no one reads it aloud.

It lives in a section of the carrier's website that you only reach if you already know it exists and decide to look for it.

The practical result is that most people discover their destination's zone when reviewing an itemized bill, meaning when the consumption has already occurred and there's nothing left to do.

How to check before buying your ticket

This is the most useful advice in the entire text and it costs nothing.

Before finalizing a trip to a destination that isn't the United States, Canada, Western Europe, or Latin America, it's worth dedicating ten minutes to the following:

1. Go to your carrier's website, to the roaming or international roaming section.
2. Look for the list of countries by zone and locate your specific destination.
3. See what packages exist for that zone, including the data amount and price.
4. Jot down that number in your trip budget, alongside your flight and hotel.

If the destination falls into an expensive zone, that single check changes the entire planning. And if it falls into the good zone, you travel with peace of mind knowing why.

The error of calculating by days instead of by zone

There's a very common way of thinking that leads to wrong decisions, and it's worth pointing out because it's counterintuitive.

Many people estimate the data cost of a trip based on its duration. Ten days cost more than four, twenty more than ten. It seems logical.

In practice, the most important factor is not the duration but the zone. A short trip to an expensive category destination can be much more costly in data than a long trip to a good list destination, even if the latter lasts three times as long.

This leads to a simple rule for planning: the first question is not how many days am I going, but where am I going. And that question is answered by consulting the table, not by calculating.

There's a second related error. When someone travels to an unusual destination, they usually research a lot about visas, vaccinations, safety, and transportation, and almost nothing about connectivity. And yet connectivity is precisely the variable that changes the most in these destinations, precisely because they are the ones that fall outside the preferred zones.

The alternative that doesn't depend on the carrier's zone

There is another path, and its main advantage is precisely that it ignores that table.

Data plans for specific destinations, purchased from Mexico before traveling, bypass your own carrier's toll. You directly contract access to local networks in the destination country, with a fixed price paid in advance.

This has three specific effects on the problem described in this text:

1. The price is known beforehand and doesn't depend on which category the country falls into on an external table.
2. No open consumption remains, so there's nothing that can appear on your bill weeks later.
3. Destinations that fall into the carrier's most expensive zones are precisely where the difference is most noticeable.

Plastic SIM cards are no longer necessary: these are digital profiles, a file downloaded to your phone from home. Your Mexican SIM card stays in, so your number, WhatsApp with all its groups, and bank messages continue to work as usual. The only thing that changes is where the data comes from.

In the case of PuraSIM, there is coverage in over 200 destinations, the plan days run from the first use and not from purchase, and you have 180 days to install it. This means you can buy it today, install and test it at home, and travel two months later without losing a single day.

Frequently asked questions

What if I travel to several countries on the same trip?

It's advisable to check each destination before purchasing, as some plans cover multiple countries in the same region while others do not. This is exactly the kind of detail that's best resolved at home, not on a train platform.

Do I still need to pay for my Mexican plan?

Yes, your Mexican line remains yours and is paid for as usual. What you're buying is an additional data plan just for the duration of your trip.

Does it work for local phone calls?

Data plans do not include a local number. Calls are made via messaging apps. It's good to know this beforehand if your trip involves procedures that require a local phone number.

How do I check if my cell phone is compatible?

Open the dial pad and type `*#06#`. If, in addition to the IMEI, an EID number appears, your device supports digital profiles. Two Mexican warnings: several Redmi and Xiaomi phones sold here are Latin American versions and do not include it even if the international specifications say otherwise, and being unlocked is not the same as being compatible.

What to remember

• Mexican carriers apply zones, not a single international rate.
• The difference between zones is not percentage-based: it can change the order of magnitude of the expense.
• The table is published, but it does not appear at any of the times when it would be useful to see it.
• Cruises have their own rates because the phone connects to the ship's antenna.
• Checking the destination zone before buying the ticket takes ten minutes and avoids the entire problem.

PuraSIM sells destination-specific data plans that are purchased and installed from Mexico before traveling, with a fixed price, for over 200 destinations. Customer service is available via email and WhatsApp, with people who respond in Spanish. There is no phone support.