The "unlimited" package that comes with a hidden number, and how to find it before paying

There is a way to run out of internet on a trip that never comes up in conversations about roaming, because it doesn't fit the usual story.

It's not the person who forgot to turn off mobile data. It's not the one who trusted the hotel Wi-Fi. It's the person who did everything right: purposely bought a travel package, paid upfront, and by day three their phone is so slow they stop trying.

There was no surprise charge. There was no mistake. They got exactly what was published.

The problem is that what's published and what's advertised are not the same thing.

No data plan is truly unlimited

It's worth starting here, because it dismantles half the issue.

No company in the world offers data with absolutely no limit. Every single one has a fair usage policy: a threshold after which they reduce your connection speed.

The word that appears in the ad describes the absence of a hard cutoff. It's true they don't cut off your service. What the fair usage policy does is drop your connection to a speed so low that, in practice, it's no longer useful for what you need.

So the useful question is never whether the plan is unlimited. The useful question is what the number is and where it's written.

Where the number is published

In the case of AT&T Mexico's international packages, the figure is on their own site, in the same table where the price appears.

Their 5-day Preferente package costs 299 pesos and includes 2,500 MB. After exceeding that amount, the speed is reduced to 256 kbps. The 10-day package costs 549 pesos with 5,000 MB, and the 17-day package costs 849 pesos with 8,500 MB. The World Zone packages follow the same logic with different prices.

Source: att.com.mx, plans and international roaming section. Prices include VAT.

None of this is hidden. It's published, on their website, right next to the price.

What happens is that the big word is what sticks, and the number is in a column off to the side.

What 256 kbps actually means in real life

It's an abstract number until you translate it.

At that speed, text messages still come through and notifications arrive. Almost everything else stops working well:

• A map with real-time traffic takes so long to load it's useless when you're walking.
• Scanning the code for a menu on a restaurant door can take several minutes.
• Sending a photo to your family becomes a long wait.
• A video call is not viable.
• Loading a reservation confirmation from an app is slow and unreliable.

In other words, minimal communication survives, and everything that makes a phone useful while traveling disappears.

How much data you actually use on a trip

This is the part almost no one calculates beforehand, and it's what determines whether a limit is generous or tight.

As a rough reference to give you an idea, not a promise:

• Navigating maps with the screen on is one of the most constant uses throughout the day.
• Photos that automatically back up to the cloud can be the biggest data drain of the trip without you even noticing.
• Videos and stories on social media consume much more than messaging.
• Plain text messaging uses very little.

From this comes a practical tip that works with any plan: turn off automatic photo backup while traveling and leave it for when you have Wi-Fi. It's the setting that makes the biggest difference, and almost no one touches it.

Why the word still works even though almost no one believes it

It's worth understanding why the whole category insists on the same adjective, because it explains a lot about the market.

A number forces comparison. If one plan says a specific amount and another says a different one, the buyer has to estimate how much they'll use, and that takes work and risks being wrong.

An adjective removes that discomfort. It sounds like there's nothing to think about. And for someone traveling who just wants to get it out of the way, not thinking is exactly what they're looking for.

The problem is that peace of mind lasts until the third day. And from there, the traveler usually blames their phone, the area, or the hotel, because at no point were they told a threshold existed. That's the real cost of the word: it's not that it deceives, it's that it leaves the user without the information needed to understand what's happening to them.

That leads to a simple recommendation that applies to any provider. When an ad uses that adjective, look for the figure on the same page. If the figure appears next to the price, the seller is playing fair. If you have to go three screens deeper to find it, that says something on its own.

The other fine print: the destination zone

There's a second variable that can matter more than the speed cap, and that's which zone the destination country falls into.

Mexican carriers don't apply a single international rate. In the published catalog, a 15 GB package for the US, Canada, Latin America, and Europe coexists with a Rest of the World package of 20 MB for 6,000 pesos.

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

The same traveler can buy the same class of product for two different destinations and get radically different things. That's why it's worth checking the zone before buying the plane ticket, not after.

What to check before signing up for any travel plan

A short list that works for any provider, including this one:

1. What the exact data amount is, in gigs or megs. If the ad doesn't say it, look for it.
2. What happens when you exceed it: whether speed is reduced, service is cut off, or you're charged per use.
3. Which zone the destination country falls into.
4. When the days start counting: from purchase or from first use.
5. Whether you can share data with another device.
6. Who handles it if something goes wrong, and through which channel.
7. Whether a refund, if it doesn't work, is in cash or as credit to buy again.

The last two are the ones most people skip and the ones that matter most the day something goes wrong.

The alternative: a number instead of a word

Opposite the model of the big word with the hidden number is the opposite model: buying a specific amount and knowing it from the start.

Destination-based data plans bought from Mexico before traveling work like this: a set number of gigs and a set number of days, with a fixed price paid upfront. When it runs out, it runs out, and there's no open usage that could show up on a bill weeks later.

It's not a more generous model. It's a more readable model. You can do the math with a number. You can't do the math with an adjective.

In PuraSIM's case, some plans have a daily allowance, and their label shows the speed after the day's allowance is used, precisely so that information is visible and not two screens deeper.

Also, the days run from first use at the destination, not from purchase, and you have 180 days to install it. That means you can buy it today, install and test it at home this week, and travel in two months without losing a single day.

That detail matters more than it seems for a reason that isn't about price: installing the plan at home, with wifi and days of margin, turns any problem into a twenty-minute annoyance. Installing it on arrival turns the same problem into the first night of your trip.

Before anything, a ten-second check

It's worth checking that your device supports digital profiles before you pay for anything. Open the dial pad and type `*#06#`. If a number called EID appears next to the IMEI, the device is good to go.

Two warnings for Mexico: several Redmi and Xiaomi models sold in the country are the Latin America version and don't include the component, even if the international spec sheet for the same model says they do; and being unlocked is not the same as being compatible.

What's worth keeping in mind

• No data plan is truly unlimited. Every one has a fair-use policy with a published threshold.
• On AT&T Mexico international packages that threshold appears next to the price: 2,500 MB on the 5-day plan, with a reduction to 256 kbps.
• At 256 kbps messaging survives and almost everything else disappears.
• The destination area can drastically change what you get for the same type of product.
• It's worth searching for the number, not the word, and checking it before you buy your ticket.

PuraSIM sells data plans by destination that you buy and install from Mexico before you travel, with a fixed price, for more than 200 destinations. Customer support is by email and WhatsApp, with real people answering in English. There is no phone support.