If you have planned a longer stay in China, buying a Chinese SIM card may be a sensible decision. It is an economical solution to stay in touch with your relatives and friends because most SIM cards provide you with free incoming calls with the non-free ones costing you a mere 0.07 dollars per minute, rather affordable. You can also enjoy local mobile network service and rates for calls, data, etc. In addition, most Chinese apps only support Chinese phone numbers.
There are mainly three mobile operators – China Mobile, China Unicom and China Telecom whose branches can be easily found in Beijing. They serve special short-term pricing packages for passport holders. They have branches set up at Beijing International Airport (PEK). CMCC (China Mobile) Service Office situates at T2 while China Unicom Service Office is found at T3. Both will offer you special short term packages so be sure to see through all their available offers. In addition, you'd better make it clear which communication carrier your mobile fits in advance.
It should come to attention that you need to show your passport details to get a SIM card for real-name system is implemented in China. Hence, you need to show your passport when you purchase the SIM card.