Yingli expects shipments to grow rapidly in markets like China in the fourth quarter, while JA Solar said it was making inroads into Australia, Southeast Asia and South America.
JA Solar's third-quarter shipments to China doubled from the preceding quarter. China contributed 28 percent to Yingli's quarterly revenue, compared to 14 percent in the second quarter.
Rival JinkoSolar Holding Co Ltd earlier this month said half of its 2013 revenue would come from China.
China has launched a number of incentive programs to prop its flailing solar industry and in August hiked its 2015 target for solar power capacity by 40 percent to about 21 gigawatts (GW), the third increase in just over a year.
The United States earlier this month approved tariffs on imports from most top Chinese solar equipment manufacturers, including Yingli and JA Solar.
The European Union is looking at imposing similar duties and has launched an investigation into alleged state subsidies for Chinese solar panel manufacturers.
These developments in top market Europe and the United States come at an unfortunate time for Chinese solar companies, whose margins have nearly disappeared due to a sharp fall in prices.
Prices have plunged 75 percent in the last four years on weak demand from Europe and rapid capacity expansion.
Betting on Power Plants
Yingli also said it would ship 200 megawatt (MW) of modules to a utility scale project in Imperial County, California, being developed by Centinela Solar Energy LLC.
Solar companies are turning to the more lucrative business of developing large solar power plants that will be powered by their panels, as pure panel manufacturing remains highly unprofitable.
Rivals Trina Solar Ltd and Canadian Solar Inc have also said they are turning their focus to utility-type solar projects.
JA Solar, which consolidated its American Depositary Shares (ADS) last week to avoid delisting from the Nasdaq, said it expects total cell and module shipments to be between 380 megawatt (MW) and 420 MW in the fourth quarter, compared with 418 MW in the third.
The company narrowed its full-year shipment outlook to between 1.55 GW and 1.65 GW, from 1.5 GW to 1.8 GW.
The bleak shipment forecast comes days after rivals Trina Solar and Canadian Solar cut their full-year forecast for solar panel shipments.
Yingli shares have lost nearly two-thirds of their value this year, while those of JA Solar have more than halved.