Japanese phone company NTT DoCoMo is to sell its stake in a joint venture with America Online (AOL) to the US Internet firm.
Many Japanese mobile phone users want to access the Internet
AOL will buy DoCoMo's 43% stake in DoCoMo AOL, as well as the holdings of its other Japanese partners.
The venture was formed to offer mobile phone users quicker Internet access and a wider range of services.
DoCoMo is Japan's biggest mobile phone company; AOL is part of the world's largest media company Time Warner.
The companies did not give a price or time for the sale.
DoCoMo is seen by many as a pioneer in the mobile telephone industry following its success in getting customers to sign up to ultra-fast 3G services.
3G allows subscribers to surf the internet and send audio and video clips using their handsets.
Even so, consumer appetite for the new services has been lukewarm and analysts have voiced concerns that mobile operators may have difficulty recouping their investment.
AOL, meanwhile, has suffered as dotcom fever subsided.
Back in October, Time Warner dropped the AOL tag from its name and the Internet service provider has seen rivals eat into its market share.
Sales and profit have dipped as a result.