Travelling to China with a blackberry Z10. I will not need to make calls, only use Internet.

Hettie, if you don't have international roaming data package or the package is too expensive, then you may try to buy a local sim card when you arrive. I guess your Z10 supports WCDMA, right? If so, you should buy a sim card and data package from China Unicom Office Branches. You know, the related authorities require that all cellphone owner need to register their sim cards with their valid ID cards. For you, you need to provide your passport.

Before you go back, you'd better go to the office to cancel your sim card. It sounds very complicated, right? So I personally think that you may consult with your telecom operator and ask if there is relatively cheap international roaming data package for a month or just several days. If so, you can subscribe it and save the trouble buying and cancelling Chinese simcard.