According to the Diffusion Group, by the end of the decade both Windows and Linux will have greater market share than Symbian.
In 2010, the analyst house said, Symbian will see its market share halved to around 22 percent, while Windows will climb to more than 28 percent and Linux to more than 26 percent.
The Diffusion Group said the change will come about as 3G networks enable more advanced applications made possible by the likes of Microsoft and Linux.
Currently, Symbian shipments dwarf those of rival Microsoft. At last week's 3GSM conference, Symbian announced its 2005 shipments had reached 33 million for the year. Microsoft said it had shipped five million devices in the same period.
In a recent interview with ZDNet Australia sister site Silicon.com, Jørgen Behrens, vice-president of product management and strategy at Symbian, said he considered Microsoft and Linux less of a commercial threat than the own-brand OSes used by handset vendors on their mid-range phones.
He said: "Microsoft are years behind us. We have the battle-hardened robustness that you get on a system... on 200 networks in 70 countries, rather than just odd operators in odd countries."
Silicon.com's Jo Best reported from London. For more coverage from Silicon.com, click here.
