A Chinese phone number is often much more than just a SIM card. For many expats, it is linked to WeChat, Alipay, bank accounts, apps, government services, and verification codes. Losing access to that number can create real problems, especially if the number is later recycled and assigned to someone else.

Here are a few practical things worth knowing.

1. Your monthly data SMS may not show your balance

Many China Mobile users receive regular messages showing how much data they have used or how much data remains. These messages usually do not show how much money is left in the account.

To check your balance quickly, send an SMS to your carrier:

China Mobile: send YE to 10086
China Unicom: send 102 to 10010
China Telecom: send 1 to 10001

For China Mobile data usage, send CXLL to 10086.

Replies usually arrive within seconds. Commands can vary by province or plan, so if one does not work, try the carrier app or WeChat mini-program.

2. Old SIM cards can still be linked to your accounts

Many expats have used more than one Chinese SIM card, especially after moving cities, changing carriers, or replacing an old number.

The problem is that old numbers do not simply disappear. If a prepaid number reaches zero balance and remains inactive, it may eventually be suspended, deregistered, and recycled. A commonly reported timeframe is around 90 days, though this can vary by carrier and plan.

That matters because your old number may still be linked to important accounts. WeChat, Alipay, banking apps, delivery apps, and government services may continue using that number unless you actively change it.

For WeChat, there is a known process where a recycled number can be unbound from the previous user if the new user confirms the number has been recycled. For other platforms, such as Alipay and banking apps, the exact behaviour is less clear.

The safest approach is simple: update your phone number in important apps before abandoning an old SIM.

3. You can pay a small fee to keep an old number

All three major carriers offer a service called 停机保号, which means service suspension with number preservation.

With this service, calls and data are suspended, but the number is protected from recycling as long as the monthly fee is paid.

Reported monthly fees are roughly:

China Mobile: 8–10 RMB/month
China Unicom: 8 RMB/month
China Telecom: about 5 RMB/month

Fees may vary by province, plan, or registration type, so confirm with your carrier first.

Foreign passport holders can usually request this service, but it may require calling customer service or visiting a carrier store with your passport.

4. China Mobile users should set up 无忧行 before travelling

If you use China Mobile and travel outside China, the 无忧行 app can be very useful.

The app, published by China Mobile International, has a feature called 号码托管, or number hosting. Once activated, it allows your China Mobile number to receive incoming calls and SMS through the app over WiFi or mobile data, even without the physical SIM inserted or roaming active.

This can be helpful for receiving verification codes while abroad.

To set it up:

Download 无忧行 while your Chinese SIM is still active.
Log in with your China Mobile number and complete SMS verification.
Switch your phone from 5G or VoLTE to 4G.
Deactivate or remove the China Mobile SIM.
In the app, go to 电话/消息 → 号码托管 and activate the service.

Once active, incoming calls and SMS should appear in the app through an internet connection.

A few important notes:

The app is in Chinese only.
Outbound SMS is not supported.
Outbound calls may be charged.
If the physical SIM reconnects to the network, number hosting may deactivate.
It is much easier to set this up before leaving China.

China Unicom and China Telecom users should contact their carriers directly to ask what options are available for receiving SMS abroad.

Final reminder

Before throwing away or ignoring an old Chinese SIM, check what accounts are still linked to that number. Updating your bindings, preserving the number, or setting up travel access can save a lot of trouble later.