Postmarks / eSIM education
The eSIM curriculum
Thirty short lessons, from "what even is it" to "fixing it on a ferry". Read in order if you're new; jump straight to your problem if you're not.
{count} lessons · ~{hours} hours total
Basics
START HERE · Nº 01-06
Nº 01
What is an eSIM? A plain-language guide
No jargon. What an eSIM actually is, how it differs from a plastic SIM, and why travellers adopted it first. A plain guide before your next trip.
{n} MIN · MARTA KOWALSKA
Nº 02
eSIM vs physical SIM: what actually changes
A clear comparison of eSIM and physical SIM cards - what's identical, what's different, and the two situations where plastic still beats software.
{n} MIN · MARTA KOWALSKA
Nº 03
Is your phone eSIM compatible? The full list
Which iPhones, Galaxy and Pixel phones support eSIM, plus the mainland China and US-locked exceptions, and the 30-second test to check your own.
{n} MIN · MARTA KOWALSKA
Nº 04
How to install an eSIM in two minutes
A step-by-step guide to installing an eSIM: what you need first, the actual install steps, and how to confirm it worked before you travel.
{n} MIN · MARTA KOWALSKA
Nº 05
Activate before you fly: the pre-flight ritual
Why installing your eSIM days before departure - not at the gate - matters, and the exact settings to check so it wakes up the moment you land.
{n} MIN · MARTA KOWALSKA
Nº 06
Data roaming explained (and why it costs so much)
What mobile data roaming actually is, why your home carrier charges so much for it abroad, and how a travel eSIM sidesteps the whole arrangement.
{n} MIN · MARTA KOWALSKA
Before you fly
Nº 07-20
On the road
Nº 11-24
Fixes
Nº 10-27
Deep cuts
Nº 18-30
POP QUIZ · TOOL
Will thy phone take an eSIM?
HOMEWORK, THE FUN KIND
Done reading? Pick a destination and try lesson four for real.