The company's Telcel subsidiary will sell Alcatel One Touch phones with Mozilla's browser-based operating system.
Thanks to Singapore-based startup U2opia Mobile, users of low-cost phones in areas devoid of a mobile data connection will be able to access a stripped-down version of the social network.
Mobile network operators at Mobile World Congress press for better government treatment, fewer free services, and no unlimited data plans.
The Spanish company's new Firefox OS phone will include a "high-performance processor" and can run Google's Android operating system, too. The company hints it could use an Intel processor.
Among additions to the new browser-based OS are support for MMS, keyboard autocorrect, and a home screen that makes it easier to find apps. Also new: broader carrier plans for Firefox OS.
The nonprofit organization is trying to give programmers better tools for writing Web apps for its mobile operating system.
Mozilla may have figured out a way to get its shiny orange and blue Firefox phones into the hands of fans in the U.S. and U.K. But that doesn't mean that analysts are any less skeptical about its chances.
The microblogging site says it will have an app available for the browser-based mobile operating system when handsets launch in the next couple of months.
Starting Friday, the company will begin selling Alcatel's One Touch Fire with Firefox OS in 850 stores in Poland, with sales in Greece and Hungary to follow in the fall.
ZTE, maker of decent budget Android gear, says it will release smart phones running the new Firefox OS next year.