With more than 700 million subscribers, China Mobile is the largest phone carrier in world. By comparison, it is seven times larger than Verizon Wireless, the largest phone carrier in the United States.
The deal could bump global iPhone sales by 17 percent. Research firm Trefis said China Mobile could sell about 1.5 million iPhones each month or nearly 20 million by the end of 2014.
Sales are expected to begin mid-December.
Apple already has contracts with two smaller phone companies in the country, China Unicom Hong Kong Ltd. and China Telecom Corp., which began selling iPhones in 2009 and 2012, respectively. But their subscriber numbers are smaller than China Mobile's.
China Mobile's iPhone sales are coinciding with the company's move to a 4G network. About a quarter of its customers use its 3G network, while the remainder use older systems.
Apple had been wary of signing a deal with China Mobile with an older and less reliable network. China Mobile, in turn, had been wary of signing a deal with Apple that included a minimum guarantee for iPhone sales, the Journal said.