CALGARY, Alberta (Reuters) - Third-quarter profit at Canadian Oil Sands Ltd (COS.TO: Quote), the biggest partner in the Syncrude Canada Ltd joint venture, rose 25 percent on higher oil prices and increased production, the company said on Thursday.

The company, which as a 37 percent stake in Syncrude, one of Canada's largest oil sands producers, earned C$242 million ($244 million), or 50 Canadian cents per share, up from its year-earlier C$193 million, or 40 Canadian cents.

Cash flow, a glimpse into the company's ability to fund its development projects was C$512 million, or C$1.06 per share, more than double year-prior quarter's result of C$230 million, or 48 Canadian cents per share.

Canadian Oil Sands said its results were helped by a 26 percent rise, to C$97.89 per barrel, in the price of the light synthetic crude produced at the Syncrude site in northern Alberta.

During the quarter, production rose 13 percent to 109,260 barrels a day net to the company.

Operating costs were C$37.19 a barrel, down 2.1 percent on lower natural gas costs.

The company maintained its 2011 forecast for total Syncrude production of 301,400 bpd, despite the unplanned shutdown of a hydrogen unit earlier this month that some observers estimate has reduced production by more than 40,000 bpd.

Canadian Oil Sands' work on the unit will extend into early December. However Syncrude has stockpiles of bitumen that can be upgraded after the unit is repaired, allowing the project to stick to production forecasts.

Canadian Oil Sands shares closed up 3.7 percent at C$24.28 on the Toronto Stock Exchange on Wednesday, but down 8.2 percent since the start of the year. In the same period, the TSX energy group has fallen 13 percent.

($1=$0.99 Canadian)

(Reporting by Scott Haggett; editing by Rob Wilson)