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Installing a China eSIM before you fly, step by step, with fixes for no signal

Home install steps for iPhone and Android, roaming settings, keeping your Thai SIM for SMS, and fixes for problems after landing.

Author: Bob Kanokphon Thongdee · Co-founderReviewed by: Porsch Kunnipat SiramanakulPublished: October 13, 2026Last updated: October 13, 2026
Installing a China eSIM before you fly, step by step, with fixes for no signal

Quick answer

  • Install the eSIM at home over Wi-Fi before flying, because the QR scan needs internet and the seller's site may not open in China.
  • Set the eSIM as the data line with roaming on for the eSIM only; keep the Thai SIM on for SMS but with data roaming off.
  • If there is no signal after landing, restart, toggle airplane mode, select the network manually and check the roaming switch.

Check first: eSIM support and carrier lock

Installing a China eSIM is easy, but do it at home before you fly: you need internet to scan the QR code, and the seller's site may not open in China. First confirm your phone supports eSIM and is not locked to a carrier, because a locked phone refuses eSIMs from other providers.

  • iPhone: Settings > General > About; Carrier Lock should say No SIM restrictions, and an EID should be listed.
  • Android: look in Settings > Connections > SIM manager for an Add eSIM option; menu names vary by brand.
  • If you bought the phone through a carrier and are still paying it off, ask whether it has been released from the lock.
Installing a China eSIM before you fly, step by step, with fixes for no signal

Buy the plan and keep the QR code

Pick a plan using the checklist in “How to Choose a China eSIM: A Buyer's Checklist”, then save the confirmation email, the QR code and the manual install details (SM-DP+ address and activation code) offline in case you must reinstall.

Installing a China eSIM before you fly, step by step, with fixes for no signal

Install over Wi-Fi at home

Do these steps while connected to Wi-Fi. For the general overview see “How to install an eSIM, step by step (iPhone and Android)”.

  1. 1iPhone: add the eSIMGo to Settings > Cellular > Add eSIM > Use QR Code, scan the code from the email, or choose manual entry, and continue until it finishes.
  2. 2Android: add the eSIMGo to Settings > Connections > SIM manager > Add eSIM and scan the QR code, following your brand's menu.
  3. 3Label the lineName the eSIM China and the Thai SIM Thai so you never mix them up when picking a line.
  4. 4Set the eSIM as the data lineIn the cellular menu, set Cellular Data to the China eSIM and turn off automatic data switching so the phone does not fall back to the Thai SIM.
  5. 5Turn on roaming for the eSIM onlySwitch Data Roaming on for the China eSIM line and off for the Thai SIM to avoid roaming charges. Leave the Thai SIM on for calls and SMS.
Many plans do not start counting until the first connection in China, but some start at installation. Check your plan's rule before you install.
Installing a China eSIM before you fly, step by step, with fixes for no signal

When you land in China

Turn off airplane mode and wait for a Chinese network name to appear at the top of the screen. The APN is normally automatic, so enter one only if your plan provides it. Then test immediately: open the foreign apps you need, such as LINE or Google Maps, and load a web page. Do not assume every app works until you have tried it.

Last checked October 2026. App access and networks can change, so confirm with your eSIM seller before flying, and keep the Thai SIM on for bank OTPs.
Installing a China eSIM before you fly, step by step, with fixes for no signal

If there is no signal after landing

Try these in order and test after each one.

  1. Restart the phone
  2. Switch airplane mode on, wait, then off
  3. Select the network manually: turn off automatic selection and pick a Chinese network from the list
  4. Check that data roaming is on for the eSIM and that it is the data line

Troubleshooting table

SymptomLikely causeFix
Signal bars but no dataData roaming off, or data line set to the Thai SIMTurn on roaming for the eSIM and reset the data line
No network nameNot yet registered, or the eSIM line is switched offRestart, toggle airplane mode, select the network manually
Data works but foreign apps will not openThat app or network is not routed via the gateway, or hotel Wi-Fi is in useTurn Wi-Fi off, use mobile data, contact the seller
Roaming charge from the Thai SIMData roaming still on for the Thai SIMSwitch off data roaming on the Thai SIM before flying

Pre-flight checklist

  • The eSIM appears in your line list, labelled China, and is switched on
  • Data roaming is on for the eSIM and off for the Thai SIM
  • The confirmation email, QR code and manual install details are saved offline
  • Offline maps and any apps that need account sign-up are done in advance; see “Offline maps that actually work when the data runs out”
  • Alipay or WeChat Pay is set up; see “Using a Credit Card in China and Linking a Card to Alipay or WeChat Pay”

While you are in China the phone runs two lines at once: the eSIM carries data and the Thai SIM receives SMS. If a Thai bank SMS does not arrive, check that the Thai SIM is still on and registered for voice and text roaming, with only its data switched off. For calls home, try an app that calls over data; see “Wi-Fi calling abroad: setting it up so it actually works”.

One more caution: a system update or a network settings reset during the trip can return roaming settings to their defaults. After any update, open the cellular menu again, and never remove the eSIM from the phone, because it usually cannot be reinstalled from the same QR code.

If you carry two phones, install the eSIM only on the one you will actually use, because a single QR code normally works on one device only.

FAQ

Can I install it at a Chinese airport+

Not recommended: you need internet to install and the seller's site may not open. Install at home instead. See also “Wi-Fi in China: Hotels, Airports and Cafés Explained”.

Do I need to enter an APN+

Usually not, it is configured automatically. Enter one only if the seller tells you to.

Can I delete the eSIM after returning+

Yes, after it expires, but a deleted eSIM usually cannot be reinstalled from the same QR code, so never delete it during the trip.

About the author

Bob Kanokphon Thongdee

Bob Kanokphon Thongdee

  • Co-founder of eSIMonline.asia
  • More than 7 years in online marketing
  • Founder of Cojourney Visa and Cojourney Travel
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