China Mobile, which controls about two-thirds of China's mobile market, has been steadily gaining share over the last six months at the expense of its main rival, China Unicom Ltd, which analysts say has recently lacked focus.
The company boosted its subscriber base by about 10 percent to 231 million in the six months through August, compared with 7 percent growth for Unicom over the same period.
China Mobile's third-quarter profit rose to 12.8 billion yuan ($1.6 billion), based on Reuters calculations, compared with 10.1 billion yuan a year earlier.
The company was expected to report a profit of about 13 billion yuan, according to a consensus forecast from three analysts polled by Reuters.
The company added 3.87 million subscribers in September - its largest monthly gain in more than three years - bringing its total to 234.88 million as it continued to gain market share.
UOB Kay Hian analyst Hover Chen said China Mobile's average revenue per user (ARPU), a widely watched industry indicator, fell slightly to 89 yuan in the third quarter from 91 yuan in the second, based on calculations using company-supplied data for the first nine months of the year.
"We saw a lot of promotions in the third quarter so the decline is acceptable," he said. "Generally the result is in line with my expectations."
Third-quarter operating revenue grew to 61.52 billion yuan from 51.37 billion.
China is the world's biggest mobile market with 373 million subscribers at the end of August. The number is expected to hit more than 430 million by the end of next year - equivalent to one mobile account for every three of China's 1.3 billion people.
But with most affluent big-city dwellers already signed up for service, China Mobile and Unicom have had to look to more cost-conscious consumers in smaller markets for growth.
China Mobile has capitalised on its market-leading position to consolidate its position against Unicom, which analysts say has lost focus as it tries to decide whether to concentrate on its older network based on the GSM standard popular in Europe or on a newer one based on a standard called CDMA.
Analysts and industry watchers say that China Mobile is in a comfortable position heading into an industry restructuring, which most expect to be announced in the first half of next year.
That restructuring would be followed a short time later by the award of licences for high-speed third-generation (3G) mobile services. A number of scenarios have been the subject of various rumours and industry speculation, including one in which Unicom would be broken up and its two networks given to China's top two fixed-line carriers, China Telecom Corp and China Netcom Group Corp.
But few or none of those scenarios have involved major changes for China Mobile, which most industry watchers expect to emerge from any reshuffle relatively intact and with a 3G license.
Reflecting its strong position of late, China Mobile's shares rose 31 percent in the third quarter. By comparison Unicom shares lost 1.5 percent for the period, China Telecom rose 4.5 percent and Netcom rose 18.7 percent.