How to use an eSIM: buy, install, and activate on one phone

Q: Do I need Wi-Fi to install?

You need a path to the carrier SM-DP+ server: Wi-Fi or another live cellular line. eSIM-only activation without Wi-Fi exists in some regions—do not treat it as the default.

Q: How do I take the eSIM to a new phone?

iPhone to iPhone: Quick Transfer on iOS 18.4+. Android to iPhone: some carriers on iOS 26; otherwise rebind IMEI or reissue a QR. Travel packs usually cannot move.

An eSIM is a digital SIM written into the phone: there is no plastic card to eject. Plans arrive as a QR code, a carrier push, or a manual activation string. Turning on a working line is four steps—confirm the phone can store an eSIM, buy a downloadable plan, install the profile, and turn the line on and assign what it is for. Apple’s walkthrough is Set up eSIM on iPhone. For China mainland hardware and store activation, use Using eSIM with your iPhone in China mainland.

The install menus for a primary carrier number and a travel data pack look almost the same. What changes is where you buy, whether you must visit a store, and whether the QR code can be reused.

XR+

Worldwide: iPhone XS / XS Max / XR and later support eSIM

5 models

China mainland carrier eSIM: 18 Pro / Pro Max, Duo, 17e, Air

Most iPhones can store eight or more eSIMs; only one or two lines are usually active

What an eSIM is

A physical SIM is a removable chip. An eSIM is a writable chip inside the phone; the carrier sends a profile onto it. In practice:

Add a number or a travel pack without swapping cards.
Store several plans and enable one or two when you need them.
Most QR codes work once. Delete the profile and the same code often will not install again—especially travel packs.
A primary number usually transfers through the carrier. A travel pack often has to be bought again for a new phone.

Under the GSMA spec, a QR code encodes LPA:1$SM-DP+ address$matching ID. If scanning fails, entering those two fields by hand does the same job.

Checks before you buy

Run these before you pay, or you will own a code the phone cannot download:

The hardware supports eSIM. iPhone: XS / XR and later worldwide; Settings → General → About for the model. China mainland carriers only accept specific China models (below). Android: search Settings for “eSIM” or “Add SIM” and confirm the entry exists.
The phone is unlocked. A carrier-locked contract phone often rejects third-party travel eSIMs. Check “Carrier lock” in Settings or ask the original carrier to unlock.
You need a network to download. Installing a profile hits the carrier’s server over Wi-Fi or another working cellular line. Do not expect a scan to work offline. Some eSIM-only iPhones can activate without Wi-Fi in some countries; treat that as a regional exception.

Do not display the QR code on the same phone you are installing

Show it on a laptop, tablet, or printout and scan with the phone camera. A screen cannot scan itself. Exception: on iOS 17.4 or later you can touch and hold a QR code in Mail or Safari and tap Add eSIM.

Buy: primary number vs travel data

The install UI is shared. Support is not.

Primary number (calls, SMS, a local MSISDN)

Ask your carrier—China Mobile / Telecom / Unicom, Verizon, docomo, and so on—to write the existing number as an eSIM, or to open a new one. Delivery is usually:

In-store write — still required in China mainland.
eSIM Carrier Activation — IMEI bound at purchase; a “Cellular Plan Ready to Be Installed” banner after setup.
App or emailed QR code — more common outside China.

A primary eSIM is tied to identity and the phone number. Move it with Quick Transfer or the carrier, not as a disposable data pack.

Travel / data eSIM

Buy coverage by destination and days—usually data only, no local number. You get a QR code or an LPA:1$ string immediately. Check:

The first country you land in is covered (including a layover that needs data).
Whether the pack starts on install or on first local attach.
Install count: most travel eSIMs bind to the first phone that downloads them.
Validity start: at home before the trip, or after you land—this decides when you should scan.

World map with destination pins—check travel eSIM coverage before you pay — Match coverage first, then pay. The QR code is only the download handle; the plan lives on the carrier’s SM-DP+ server.

Install on iPhone

Settings → Cellular (or Mobile Data / Mobile Service) → Add eSIM. Older iOS may say “Add Cellular Plan”.

QR code

Open the QR code on another device; connect this iPhone to Wi-Fi.
Scan with Camera until “Cellular Plan Detected” appears, or choose Use QR Code in Settings.
Continue → Add Cellular Plan. Enter the confirmation code if asked.
Wait for the download. A new line appears in Cellular.

iOS 17.4+: touch and hold a QR image in Mail or the browser → Add eSIM. If the carrier sent a link instead of an image, open it → Allow “Activate New eSIM”.

Carrier Activation and Quick Transfer

Carrier Activation: after the carrier registers your IMEI, tap “Carrier Cellular Plan Ready to Be Installed” and continue. If the new plan replaces a physical SIM, remove that SIM and restart.

eSIM Quick Transfer (iPhone to iPhone): both devices on the same Apple Account, unlocked, Bluetooth on, iOS 18.4 or later. Transfer during new-phone setup, or Settings → Add eSIM → Transfer From Nearby iPhone. The old phone’s line deactivates when the new one activates. iOS 26 adds multi-number transfer and, for some carriers and phone makers, Android ↔ iPhone transfer—only if that carrier actually enabled it.

On the same iPhone, some carriers also let you convert the physical SIM to eSIM without changing phones.

Manual SM-DP+

If the scan fails, or you only received two lines of text: Add eSIM → Use QR Code → Enter Details Manually. Fill in:

SM-DP+ address — hostname such as smdp.example.com
Activation code / matching ID — unique to the order
A confirmation code in the third field if the carrier issued one

Do not split LPA:1$host$matching-id on the wrong $. An extra space fails the download.

Install on Android (Pixel / Samsung)

Menu names vary; the path is the same: network → add eSIM → scan or paste → download.

Google Pixel: Settings → Network & internet → SIMs → Add SIM / Add eSIM → scan. If that fails, use Need help? and paste the full LPA:1$ string.
Samsung Galaxy: Settings → Connections → SIM manager → Add eSIM → scan. Manual entry is often “Enter activation code”. Samsung’s own notes say restart after install.
Other Android: search Settings for “eSIM” or “Download SIM”. If there is no entry, do not buy a pack for that phone.

If the phone asks you to turn another eSIM off before downloading, disable the unused line—do not delete a travel profile you might still need.

Activate: labels, data line, roaming

A downloaded profile is not yet “the internet”. Do four things:

Turn the line on. iPhone: Settings → Cellular → the new plan → Turn On This Line. Android: toggle that SIM.
Rename it — “Home”, “Japan data”, “Work”—so you do not tap the wrong dual-SIM control.
Pick which line carries cellular data. Travel: keep voice/SMS on the home number and point Cellular Data at the travel eSIM. Only one data line is active at a time on typical dual SIM.
Enable Data Roaming on the travel eSIM. Turn roaming off on the home line if you do not want surprise home-carrier charges.

Some packs need a manual APN (Name / APN in the email). iPhone: that eSIM → Cellular Data Network. Android: Access Point Names → add a row.

Finish with a webpage, and a test call if this is a voice line. The status bar should show the carrier name or 5G / LTE.

Dual SIM split

Typical mix: physical SIM or home eSIM + travel eSIM.

Default voice line: keep the number family already dials.
iMessage / FaceTime: can be separate from voice; confirm you are still on your Apple Account before you fly.
Cellular data: travel eSIM, switch back when you need the home network.
Some phones offer “Cellular Data Switching” when the primary has no service. Turn it off abroad if home roaming is expensive.

Most iPhones store eight or more eSIMs, but only a limited number can be on at once (dual SIM in daily use). Apple’s China mainland page says an eligible phone bought there can activate and store two eSIMs.

China mainland rules

Do not treat a global travel-QR tutorial as a China Mobile / Unicom / Telecom walkthrough.

Models (Apple, September 2026): iPhone 18 Pro (A3715), 18 Pro Max (A3718), iPhone Duo (A3721), iPhone 17e (A3635), iPhone Air (A3518). Other iPhones—including the same marketing names bought abroad—cannot install a China mainland carrier profile.
Carriers: China Mobile, China Telecom, China Unicom.
Store visit required: bring ID (and the old SIM if asked). Staff run the identity check. This is not a self-serve email QR.
Slots: Duo and Air are eSIM-only; 18 Pro / Pro Max and 17e can use eSIM or a nano-SIM.
Travel: a China-bought eligible iPhone can install a foreign or travel eSIM outside the mainland with Location Services on. You cannot install a non-mainland eSIM while you are still in the mainland. If two eSIMs are already stored, delete one to add a travel pack—restoring the deleted domestic eSIM later means another store visit.

Hong Kong and Macao still use dual nano-SIM on some models; that is a separate policy.

If install fails

Wi-Fi stability; captive or filtered office networks block SM-DP+. Try a phone hotspot.
The QR code was already used on another device.
Carrier lock, or you are in China mainland trying to install a foreign travel eSIM.
eSIM storage full. “Turn off” is not “Delete eSIM”—the latter may be irreversible for travel packs.
Manual codes with extra spaces or a missing LPA:1$ prefix.
Automatic date/time off; certificate checks fail when the clock is wrong.
Still stuck: send IMEI and EID (Settings → General → About) to the carrier and ask them to reset download count.

FAQ

How do I know this phone supports eSIM?

iPhone XS / XR and later worldwide. China mainland carriers only accept listed 18 Pro, 18 Pro Max, Duo, 17e, and Air model numbers. On Android, an “Add eSIM” row in Settings is the practical test. A populated EID in About is supporting evidence.

Do I need Wi-Fi to install?

You need a path to the carrier’s SM-DP+ server: Wi-Fi or another live cellular line. eSIM-only activation without Wi-Fi exists in some regions—do not treat it as the default.

The QR code does nothing

Use Settings → Add eSIM → Use QR Code, or touch and hold the image in Mail. Then enter SM-DP+ and the activation code by hand. Do not scan the same screen that is displaying the code.

Can I self-scan China Mobile / Unicom / Telecom in the mainland?

No. You need an eligible model and a carrier store identity check. Foreign travel eSIMs install only after you leave the mainland, with Location Services on.

If I delete the eSIM, can I reuse the QR code?

Primary number: ask the carrier to push again or visit a store. Travel pack: usually one-shot. Ask support to reset; do not assume it will work.

How do I take the eSIM to a new phone?

iPhone to iPhone: Quick Transfer on iOS 18.4+. Android ↔ iPhone: some carriers on iOS 26; otherwise rebind IMEI or reissue a QR. Travel packs usually cannot move.

In one line

The full path is check hardware and lock status → buy the right plan type → download the profile online → turn the line on and assign data/roaming. iPhone and Android menus rhyme. The usual failures are the China model list, one-time QR codes, and installing a foreign pack while still inland. After that, travel is a data-line switch.