An independent eSIM reference
Entry 02 · Activation · Sources last verified 2026-08-02
The end-to-end activation flow on iPhone, Galaxy and Pixel, followed by the failure modes behind most failed eSIM activations. Every step and every quoted phrase below is taken from the manufacturer's own published documentation, linked at the point of claim.
Apple's guidance on erasing an eSIM is unusually direct: "Don't erase an eSIM as a troubleshooting step unless directed to by your carrier." And the reason: "If you erase an eSIM, you'll need to contact your carrier to get a new one." Deleting a profile is not a reset — an eSIM profile is generally a single-use download, and removing it can leave a paid plan unusable until the provider issues a replacement. Source: Apple, How to erase an eSIM on your iPhone or iPad, published April 23, 2026. Last verified 2026-08-02
Part one
An eSIM is not a file that is copied onto a phone. It is a carrier profile that the device downloads once from the provider's server, using an activation credential. That single fact explains most of the behaviour that follows: why an internet connection is required to install one, why a QR code usually works only once, and why deleting a profile is not reversible from the handset alone.
Apple describes the eSIM as "an industry-standard digital SIM built into your iPhone, eliminating the need for a physical SIM card", and states an iPhone can "manage up to eight or more eSIMs" — stored, not simultaneously active. Samsung describes Galaxy eSIM as "a digital SIM that allows you to use the mobile data without a physical SIM card".
Install the eSIM before you leave, over Wi-Fi at home. Apple's setup documentation instructs: "Connect your new iPhone to a Wi-Fi network or hotspot", noting that only in some countries and regions can eSIM-only iPhone models activate without one. Installing a travel eSIM requires working internet — which is precisely what a traveller who has just landed does not have. Installation and activation are separate steps for most travel plans: the profile can normally be installed in advance and only starts consuming the plan when it connects at the destination, but the provider's own terms govern when the clock starts, so check them before installing.
Apple documents six routes into the same result. Which are available depends on the provider, not on the phone.
| Method | What happens | Documented path |
|---|---|---|
| QR code most common for travel eSIMs | The provider issues a QR code encoding the activation credential; the phone downloads the profile from the address inside it. | iPhone: open Camera, scan the code, tap the Cellular Plan Detected notification, then Continue and Add Cellular Plan. On iOS 17.4 or later a QR image received in the default mail app or browser can be pressed and held, then Add eSIM tapped — no second screen needed. |
| Carrier / provider app | The app installs the profile directly. | Apple: download the carrier's app from the App Store to set up an eSIM. |
| Activation link | A tappable link replaces the QR code. | iPhone on iOS 17.4 or later: tap the link, tap Allow when the Activate New eSIM notification appears, then Continue. |
| Manual entry the fallback when a QR code will not scan | The same credentials typed by hand — typically an SM-DP+ address and an activation code. | iPhone: Settings › Cellular (or Mobile Data) › Add Cellular Plan › Enter Details Manually. Galaxy: Settings › Connections › SIM manager › Add eSIM › Scan QR code › Enter activation code. |
| Carrier-pushed activation | The provider sends the profile to the device; a notification appears. | iPhone: tap the Carrier Cellular Plan Ready to Be Installed notification, then Continue. Samsung calls its equivalent eSIM Simple Setup: Settings › Connections › SIM manager › Add eSIM. |
| Transfer from another device for moving an existing number, not for buying travel data | An existing profile is moved between handsets without contacting the carrier. | Apple eSIM Quick Transfer requires both devices signed in to the same Apple Account, both on iOS 18.4 or later, both nearby with Bluetooth on. Samsung eSIM Instant Transfer states: "Your new device must be unlocked for the transfer to be successful." |
Scroll the table sideways to see every column →
Sources: Apple, Set up eSIM on iPhone; Samsung, Galaxy eSIM and supported network carriers, page updated 30 April 2026; Google, How to use dual SIMs on your Google Pixel phone. Last verified 2026-08-02
Pixel path, per Google: Settings › Network & internet › SIMs › Add SIM › Set up an eSIM. Google notes some of these steps require Android 11 or later.
Part two
In rough order of how often each one is the actual cause. Each is stated with its symptom, its cause, and the documented fix.
Symptom: the profile installs, or refuses to install, and the line never registers on a network. Frequently misread as a faulty eSIM.
Cause and fix. A travel eSIM is a second carrier's profile, and Apple's condition is explicit: "Your iPhone must be unlocked, or both cellular plans must be from the same carrier." Check at Settings › General › About: Apple states that "If No SIM restrictions appears next to Carrier Lock, your iPhone is unlocked." If that message is absent, the device is locked.
The important part is the timeline. Apple states: "Apple can't unlock your iPhone for use with a different carrier. Only your current carrier can unlock your iPhone," and that "It might take the carrier a few days to complete your request." This is not solvable at the destination. Samsung states the same requirement for eSIM transfer: the device must be unlocked. Sources: Apple, How to unlock your iPhone for use with a different carrier, published January 22, 2026; Apple, If Dual SIM with eSIM isn't working on your iPhone. Last verified 2026-08-02
Symptom: the eSIM installs cleanly, shows a carrier name and signal bars, and carries no data at all.
Cause and fix. A travel eSIM is usually a foreign profile that connects to a local network as a roaming partner. With data roaming off, the line attaches but is refused data. Airalo's help documentation states that some eSIMs require data roaming to be turned on, and that the setting is found in device settings.
The platform difference matters, and it is where bill shock comes from. Airalo documents that on iOS data roaming can be turned on per SIM — so it can be enabled for the travel line and left off for the primary line — whereas on Android "data roaming usually applies to all SIMs in use", meaning the home SIM should be turned off entirely to avoid its roaming charges. Source: Airalo Help Center, eSIM troubleshooting guidance. Last verified 2026-08-02
Symptom: roaming is on, the line is registered, and data still does not flow.
Cause and fix. The Access Point Name tells the handset which gateway to route data through. It normally arrives with the profile, but does not always. Airalo's guidance is that if data roaming is enabled and the connection still fails, the APN may need to be entered manually from the value the provider supplies, and that "If it does not connect immediately, restart your device to apply the new settings."
Two points of caution: the correct APN is the one the specific provider publishes for the specific plan — a value copied from a forum for a different plan will not work — and the restart is part of the documented fix, not superstition. Source: Airalo Help Center, APN settings guidance. Last verified 2026-08-02
Symptom: the new profile installs but the previous line stops working, or the device refuses to hold both.
Cause and fix. Storing many eSIMs and running several at once are different capabilities. Apple documents that iPhone 13 models and later support Dual SIM with two eSIMs; on earlier eSIM-capable iPhones the pairing is one eSIM plus one physical SIM, so a second travel eSIM displaces the first. Google documents two eSIM profiles on Pixel 7, Pixel 7 Pro or later — and only where "your carrier allows this feature".
Carrier permission is a genuine gate, not a formality. Google states that "DSDS and eSIM work with some mobile carriers" and directs users to ask their carrier. Apple's troubleshooting page adds two conditions worth checking: enterprise or corporate plans may not support the feature at all, and "If a CDMA carrier provides your first SIM, your second SIM won't support CDMA." Apple also notes that a billing-related blockage on the account will prevent setup. Last verified 2026-08-02
Symptom: a paid plan disappears from the device after being removed to "start fresh", and re-scanning the original QR code fails.
Cause and fix. This is the one irreversible mistake on the list, and it is usually made while trying to fix one of the other four. Apple's instruction is unambiguous: "Don't erase an eSIM as a troubleshooting step unless directed to by your carrier," because "If you erase an eSIM, you'll need to contact your carrier to get a new one." An activation credential is generally consumed on first use, so the original QR code is spent.
The correct sequence when a line misbehaves is: toggle airplane mode, restart the device, confirm the data line selection, confirm data roaming, confirm the APN — and only then contact the provider. Deleting the profile comes last, on the provider's instruction, never first. Apple also notes that erasing the device offers a choice to keep or erase the eSIM, and separately that cancelling a plan still requires contacting the carrier — removing the profile does not cancel billing. Source: Apple, How to erase an eSIM on your iPhone or iPad. Last verified 2026-08-02
Not faults
Apple documents this as expected: "Your iPhone can use one cellular data network at a time. When you're using one line to make a call, your other line shows No Service." Incoming calls on the other number can be answered if the carrier supports Wi-Fi Calling and it is switched on, and Apple notes that Allow Cellular Data Switching must be on to receive calls on a line that is not the designated data line. Google documents a comparable constraint on Pixel: on Pixel 8 and Pixel 8 Pro and earlier, "If you're on a call, you can't get a call through the other SIM at the same time," while Pixel 8a and later can use both SIMs for calls simultaneously, subject to mobile data being on for both, automatic data switching being on for the second SIM, and the carrier supporting Wi-Fi calling for it.
For transfers, that is the documented design rather than a fault. Apple states of eSIM Quick Transfer: "The cellular plan on your new iPhone deactivates your previous SIM when it activates." This applies to moving an existing number between devices. It is a different operation from adding a travel data plan alongside an existing line, and the two are worth not confusing when following instructions found online.
