soda Journal
What is an eSIM? eSIM vs physical SIM, explained
Short version: an eSIM is a SIM card written straight into your phone, with no plastic card to insert. For travellers it beats a physical SIM on almost every count, and the signal isn’t any worse, because both connect to the same carrier network.
What an eSIM actually is
A traditional SIM is a small plastic card you slot into your phone. It stores which carrier and number you’re on. An eSIM turns that card into a tiny chip soldered inside the phone. When you need a carrier, you download its “number profile” onto that chip with a QR code. No plastic, no swapping, all in software.
Put another way, an eSIM isn’t a different kind of network. It just moves the SIM from a plastic card to a piece of data inside your phone.
eSIM vs physical SIM: the differences
| Physical SIM | eSIM | |
|---|---|---|
| Getting one | Buy a card, wait for shipping or collect it | Scan a QR code and download, minutes |
| Swapping abroad | Pop out your home card and hope you don’t lose it | Keep your number, just add an eSIM alongside |
| How many you can hold | One or two, depending on the tray | Many profiles, switch anytime |
| Time to get online | Find a shop, queue, swap | Install before you leave, roam on landing |
| Easy to lose | The card is tiny and easy to misplace | Nothing physical to lose |
The last two matter most for travel. You can set up the eSIM at home, and the moment you land you turn on data roaming and you’re online, with no hunting for a shop or a counter.
The same arrival, two very different mornings
Picture two people on the same flight into Tokyo, one on a physical SIM and one on an eSIM. The gap shows up the second the plane lands.
The physical-SIM traveller has to find a counter or convenience store that sells one, queue up, dig out the ejector pin, pop out their home card and stash it somewhere safe (don’t lose it, that’s your home number), slot the new card in, and wait for it to activate. Fifteen minutes if it goes smoothly, half an hour if there’s a line or the machine won’t read the card. The whole time they want a ride or directions, they’ve got no signal.
The eSIM traveller set theirs up at home. Wheels touch the tarmac, they flip on data roaming, and they’re online in seconds, ordering a taxi while still on the jet bridge. Their home number stayed switched on the entire time, so texts and bank one-time codes kept arriving. That “online on landing, home line never drops” gap is the most concrete win an eSIM gives a traveller.
So is the signal worse?
No, and this is the most common myth. An eSIM and a physical SIM connect to the same carrier on the same network. The only difference is whether your number lives on a chip or on plastic. Signal quality has nothing to do with which one it is.
What actually decides your signal is two other things: which carrier’s line the plan runs on, and how well that carrier covers where you’re going. So when picking an eSIM, look at the line it uses, since a local native carrier is usually steadier, not at the fact that it’s an eSIM. On the same carrier, an eSIM and a physical SIM get identical signal.
Why an eSIM is the newer, better SIM
This isn’t just convenience, it’s where the industry is heading. US iPhones from the 14 onward dropped the physical tray entirely and run eSIM only, and more new phones treat eSIM as standard. Manufacturers do it because losing the tray means better water resistance, more internal space, and one less part to break.
For you the upside is concrete: no waiting on a posted card, no SIM-ejector pin, your home number untouched, and one phone holding several countries’ eSIMs to switch between. It does everything a physical card does and hands you extra flexibility. The one thing to check first is whether your phone supports it: see does your phone support eSIM.
So does an eSIM have any downsides?
In fairness, after all that praise, here are the limits, so nothing catches you off guard. First, moving to a new phone isn’t as instant as a physical card. You pop a plastic SIM into the new handset and you’re done; an eSIM usually has to be deleted on the old phone and downloaded fresh on the new one. (For a short trip eSIM you throw away after the trip, this barely matters.) Second, older phones and some regional versions don’t support it, so always check your model before buying. Third, the QR code you install from can normally be scanned only once and binds to a single phone, so don’t scan it before you actually mean to install, and don’t treat it as something you can pass to a friend.
Most of these are “one extra step when you swap phones” sized problems, and they hardly touch a short trip abroad. Knowing they exist just means you won’t be surprised.
How soda pushes that flexibility further
An eSIM already makes switching carriers a software job. soda wants to remove the “pick a plan” step too. You don’t choose a country or a number of gigabytes; you land, use it, and we bill by actual usage, capped at the cheapest plan price. Nothing is wasted, because you never bought a bundle in the first place, and your balance never expires. soda runs on stable, quality local lines and treats a steady connection as the floor. It isn’t the cheapest card out there, but whether your day is spent loafing in the hotel or navigating around town for hours, you never come out behind. The reasoning is in why you shouldn’t gamble on a travel data plan.
Common questions
Can I keep my home number while using an eSIM? Yes. An eSIM is an extra line, so you don’t pull your physical SIM. Your home number keeps receiving texts and calls, and the eSIM just handles local data. In settings, point your default data line at the eSIM.
Can one phone hold two eSIMs at once? Most eSIM-capable phones can store many profiles and keep one or two active at the same time. How many you can run simultaneously depends on the model, but storing several and switching between them is almost always possible, which is handy when you go abroad and come home.
Can I reuse an eSIM QR code or share it with someone? Usually not. An install code can normally be activated only once and binds to a single phone. So don’t scan it before you intend to install, and don’t count on splitting one code with a friend.
Does my eSIM still work after I switch phones? A short trip eSIM usually expires after the trip, so there’s nothing to move. A long-term eSIM has to be deleted on the old phone and re-downloaded on the new one, and some carriers make you re-request it. It isn’t as instant as moving a plastic card across.
How do I know if my phone supports eSIM? The quickest check is whether your phone’s settings have an “Add eSIM” or “Add mobile plan” option, or just look up the model. Recent US iPhones are eSIM-only, while some Asian versions still keep a physical tray, so confirm before you buy: see does your phone support eSIM.
(eSIM support varies by phone model and regional version; check your phone’s settings.)