Will the SIM switch to the China+ IMSI as soon as it enters China automatically or after some time?
The point of switch to the China+ IMSI also depends on the device. The "SIM Application Toolkit" will switch automatically as soon as the device notice, that the country/region is changed.
1NCE Shop

Buy the 1NCE IoT Lifetime Flat now

Visit the 1NCE Shop and start connecting your IoT devices easily. Simply choose the desired type of SIM card, order your SIM cards, and fill out all required forms. After the payment has been approved you will receive your cards within two to three business days. 

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