Quick Answer
Buy a SIM only at official telecom counters, register with your passport, and fully test data before you leave the counter.
If the SIM does not pass all tests, do not leave—replace it immediately.
Keep your home SIM if you need verification SMS for banks or payments.
Before You Buy: Make One Decision First
Before you talk to any staff, decide which of these applies to you:
You MUST keep your home SIM if:
- You need bank or card verification SMS
- You use 2FA for email, payments, or work apps
Use a dual-SIM phone, or store your home SIM safely and reinsert it later.
You may replace your home SIM if:
- You do not need SMS verification during the trip
- All important apps are already logged in
If you are unsure, keep your home SIM. Losing SMS access causes the most first-day failures.
Exact Actions: Buying a SIM Without Risk
1. Go to an official telecom counter only
- Follow airport signs for Telecom / SIM / China Mobile / China Unicom / China Telecom.
- The counter must be:
- Fixed (not a roaming seller)
- Behind a desk
- Registering passports
- If counters are closed, use airport Wi-Fi and buy a SIM in the city later.
If a seller approaches you away from a counter, do not buy.
2. Choose a simple plan
- Confirm duration, data size, and total price.
- Avoid add-ons, upgrades, or unclear bundles.
- If the explanation feels rushed or confusing, downgrade to a simpler plan.
Simple plans fail less often.
3. Register with your passport
- Hand over your passport for registration.
- If asked for an address, show your hotel address in Chinese.
- Wait until staff confirms registration is complete.
Do not insert the SIM until registration finishes.
4. Activate and TEST at the counter (this is mandatory)
A SIM is not working unless all required tests pass.
Insert the SIM and confirm:
- Signal bars appear
- Mobile data is enabled
Test ALL of the following:
- Open a browser and load a page
- Open a map app and load your current location
- Open Alipay or WeChat and confirm the app loads
- If you need SMS: receive a test message on your home SIM
If any test fails:
- Ask staff to fix APN or settings
- Or replace the SIM
- Do not leave the counter
5. Confirm your home SIM status
- If your phone supports dual SIM, keep the home SIM active.
- If you remove it, store it securely and note where it is.
Many payment and email problems happen hours later because the home SIM was removed.
Failure Scenarios & Fixes
- No signal after insertion: SIM not activated → replace it at the counter.
- Signal but no data: APN issue → fix with staff or replace SIM.
- Apps load but payments fail: do not leave → re-test or replace.
- Plan details unclear: downgrade to a simpler plan.
- Seller is not at a fixed counter: do not buy.
- Counter is closed or out of stock: use airport Wi-Fi and buy a SIM in the city.
- SMS needed later but SIM removed: reinsert home SIM immediately.
Leaving the counter without a fully working SIM is the most common mistake.
Reality Check
- You are tired, jet-lagged, and want to leave—this is when SIM mistakes happen.
- Staff expect you to stay and test; this is normal.
- Replacements at the counter take minutes; fixes later can take days.
- The counter is closed at night; use airport Wi-Fi and buy a SIM the next day.
- Cancelling and replacing is routine and not rude.
What Locals Do Instead
- Locals never leave the counter without testing data.
- Locals replace SIMs immediately if anything feels wrong.
- Locals keep their main number active for verification.
- Locals ignore roaming sellers completely.
Do the same.
Checklist (Do Not Leave Until All Are Checked)
- Official telecom counter used
- Plan duration, data size, and price confirmed
- Passport registration completed
- Data tested (browser + maps + apps)
- Payment apps load successfully
- Home SIM kept if SMS is needed