What Is an eSIM QR Code? How It Works

An eSIM QR code is a square barcode encoding an activation address and a one-time code — not a phone number or the plan itself. Scanning it tells your phone where to download the actual eSIM profile from; the profile, not the code, is what lets you connect. co:sim emails this code within seconds of checkout. Most codes work only once.

#The longer answer

Technically, the QR code encodes what the GSMA's remote-provisioning standard calls an "activation code": an SM-DP+ server address (the server that holds your specific eSIM profile) plus a matching code that proves the download request is legitimate (GSMA, "What is an eSIM?"). When you scan it, your phone's built-in Local Profile Assistant software connects to that server, authenticates using the code, and downloads the actual eSIM profile, the file that carries the network credentials, directly onto the phone's embedded chip.

That distinction matters for two practical reasons. First, the QR code image itself carries no personal data or airtime — losing a screenshot of it before you've used it is a mild inconvenience (ask the provider to resend it), not a security exposure, because it only grants a download, and most are single-use. Second, once the download completes, the code has done its job; deleting the QR code image afterward doesn't affect the installed eSIM, since the profile now lives on the device itself, independent of the code that delivered it.

#Why do most eSIM QR codes only work once?

Providers deliberately expire the code after first use, so the same activation credentials can't be redeemed on a second device. If you need to reinstall (a factory reset, a lost phone, or a new device), you generally need a fresh code or a transfer flow, not a re-scan of the original image.

Apple's own transfer tooling and Android's eSIM-to-new-device transfer both exist specifically because the original QR code alone isn't meant to be reusable (Apple Support, "Set up eSIM on iPhone"). A co:sim eSIM follows the same rule — once a code has been redeemed on a device, switching to a different phone means contacting support for a fresh one, not rescanning the original.

#FAQ

#Do I need internet access to scan an eSIM QR code?

You need internet access to complete the download the QR code triggers, though the scanning step itself just reads the image and needs no connection at all. In practice, do the whole process on Wi-Fi: open your phone's cellular or SIM settings, choose to add an eSIM, and scan the code with the camera that opens inside that settings flow — both iPhone and Android use this pattern (Apple Support, Google Pixel Phone Help). If you scan it with your regular Camera app instead, most phones recognize it as a cellular plan and prompt you to continue setup, but the download that follows still needs a working internet connection to actually pull the eSIM profile from the provider's server. That's why installing a co:sim eSIM at home on Wi-Fi, before departure, works better than trying to install it after landing on unfamiliar airport Wi-Fi.

#Can I install an eSIM without a QR code?

Yes. Every major eSIM provider also offers manual entry as a fallback: instead of scanning, you type an SM-DP+ server address and an activation code directly into your phone's eSIM setup screen. This exists specifically for situations where scanning isn't practical — a damaged QR code image, a screen that won't display properly, or a code that was read aloud over a support call rather than shown visually. Apple's iPhone setup flow and Android's eSIM menu both include a manual-entry option alongside the QR scanner, usually labeled something like "Enter Details Manually." A co:sim eSIM ships as a QR code by email, but that same email also includes the manual activation details as a backup, so a scanning problem on the day of travel never turns into a blocked install with no alternative path forward.

#Is an eSIM QR code the same as a barcode on a physical SIM card's packaging?

No, they solve different problems entirely. The barcode on physical SIM packaging is typically just a retail identifier used for purchase and inventory tracking; it plays no role in activating the SIM once inserted, since a physical SIM already carries its network credentials on the card itself, no code required. An eSIM QR code, by contrast, is the delivery mechanism for those same kinds of credentials — it's how a network profile gets onto a device that has no card slot to insert anything into. That's the core trade-off between the two formats: a physical SIM ships its credentials on hardware you physically insert, while an eSIM ships the equivalent credentials as a download triggered by scanning a code, with everything else about how the phone actually uses the resulting connection working identically afterward.

#Why does my eSIM QR code say it's already been used?

This happens when the code has already completed a successful download, either by you on a different device, or, in rarer provider-side errors, in a redemption attempt that didn't finish cleanly the first time on your current device. Since most eSIM QR codes are single-use by design, a second scan simply gets rejected by the activation server rather than issuing a fresh profile alongside the first one. If you're confident you haven't successfully installed the eSIM yet, contact the provider directly rather than repeatedly rescanning — a co:sim support request can reissue a working code quickly, and any reputable provider treats this as a routine fix rather than something a traveler has to troubleshoot alone. Rescanning the same expired code over and over won't resolve the error on its own, since the server has already marked that specific code as redeemed.

#Can someone else use my eSIM QR code if they see it?

Only if they scan it before you do, and only while it's still unused. Because most eSIM QR codes are single-use, whoever completes the download first gets the working eSIM profile, and every later scan attempt is rejected as already redeemed, which is why providers deliver the code by email or account dashboard rather than posting it somewhere public. Treat the code image the way you'd treat a one-time passcode: fine to have visible briefly on your own screen for scanning, but not something to screenshot into a shared photo album or forward casually. If a code does leak before you've used it, contact the provider immediately — a co:sim support request can invalidate the original and issue a replacement before anyone else redeems it.

Once the eSIM profile from a QR code is installed, it works exactly like a traditional SIM's credentials would — a co:sim plan for Japan or any of its other destinations is delivered the same way, by email, ready to scan before you fly.