Marc González Sáez, founder of PuraSIM

I'm Marc González Sáez and I run PuraSIM: the travel eSIM store from which I write, almost every day, about something quite specific — how to get internet on your phone when you cross a border and your carrier stops being useful or starts being expensive.

If you landed here from the footer of a guide, I'm accountable for that guide. It's not a decorative byline: the guides on the PuraSIM blog are built from our wholesale provider's network data, official carrier and manufacturer documentation and real questions from travelers, go through a check of figures and claims before they're published, and I update them when a carrier changes its roaming zones or a country changes its rules.

Why I ended up building an eSIM store

Because of the most boring and most universal travel problem: you land, turn on your phone, and nothing happens. No map, no email with your booking, no way to call a taxi. And the three classic fixes are all bad: paying your carrier's roaming without knowing the final bill, hunting for a local SIM shop at the terminal with bad exchange rates, or hopping on airport Wi-Fi and waiting.

The eSIM solves that, but brings its own traps: profiles that install but stay turned off, "unlimited" plans with a hidden cap in the fine print, validity that starts counting when it shouldn't, and support that goes silent the day you're abroad. My job is to make sure those traps don't hit the customer, and when they do, I'm the one answering.

What I specialize in

I'm not a travel generalist who also sells eSIMs. The specific ground I work on is this:

• How an eSIM actually works. eSIM profiles, EID, real compatibility per phone model, carrier lock, and why a "compatible" phone sometimes won't install anything.
• Roaming zones and pricing. What each carrier's zones actually cover, where charges kick in, and why the bill shows up weeks after your trip.
• Coverage by country. Which network a plan connects to in each destination — that's what really determines whether you'll have signal outside the capital.
• Troubleshooting. The number one cause of "I have no internet" isn't coverage: it's a profile installed but deactivated, or data roaming turned off in settings. Diagnosing that in writing, in minutes, is part of the craft.
• Comparing plans honestly. Including the cases where the right answer is "an eSIM isn't worth it for this trip."

How I work

Three things you can verify without taking my word for it:

1. I publish the data openly

The full PuraSIM plan catalog — countries, GB, days, and prices — is published as open data in a machine-readable format, so any comparison site, journalist, or curious person can audit it without asking permission. In an industry where prices are hidden until checkout, showing everything upfront is the most awkward and the most useful stance.

2. I run my own research

When I can't find the data, I collect it. One example: how much roaming actually costs in Spain in 2026, plan by plan.

3. Support is on me

PuraSIM support isn't an outsourced call center. On WhatsApp, an automated assistant that can look up your order replies first, and anything it can't solve comes to me. At hola@purasim.com you can write to me directly, including if your eSIM profile shows as disabled.

What PuraSIM is

A travel eSIM store with over 200 destinations, instant QR code delivery, and support in several languages. The project is registered in Spain, where I live and work, and also in Australia. You can read more about the company at About PuraSIM, start with what an eSIM is if it's your first time, or go straight to the plan comparison tool.

Where to find me

On LinkedIn for professional stuff, and at hola@purasim.com for everything else: customer questions, press, collaborations, or corrections to any guide. If you spot a mistake in something I've written, drop me a line and I'll fix it — it's the best way to improve 1,300 pages.