To top up your China SIM card when you run out of credit, you have several options: Dedicated kiosks and local stores. One method is to visit your mobile operator's high-street store, provide them with your phone number and cash, and they will add credit to your China SIM card. Alipay or WeChat. You can use mobile payment platforms like Alipay or WeChat Pay, but you'll need a local Chinese bank account. A Chinese friend who can top up your China SIM card using their account might also help. Online or app. Another convenient option is to top up online through your SIM card provider's website or an app like Airalo. Most providers accept payment via PayPal or major credit cards. Top-up card. Another way is to purchase a top-up card from stores with your operator's logo. These are known as "充值卡" (Chōngzhí kǎ) in Chinese and come with instructions in both Chinese and English on how to use them.