The new installations in the river Dullan, part of the River Spey catchment, were built in collaboration with the Spey Fishery Board and involved a £55,000 investment by the international drinks conglomerate.
Three and a half years in the making, the project replaces an outdated and damaged weir and will significantly improve upstream biodiversity while supporting spawning trout and salmon.
Diageo has a total of 11 single malt distilleries in the wider Spey catchment area, with its Mortlach and Dufftown distilleries currently using water from the Dullan for cooling in the distillation process.
A similar, smaller-scale project has also recently been completed on the Burn of Linkwood at Linkwood Distillery in Elgin, in the neighbouring River Lossie catchment.
Lee Oliver, environment manager at Diageo, said: "The design of the new fish pass is a vast improvement on the old, damaged weir at Dufftown and takes into account free passage for all fish species as well as different flow conditions.
"We have worked closely with the Spey Fishery Board to develop a weir system that will benefit all river users and in turn the local community. I am delighted to see the project complete and look forward to monitoring the results on fish populations over the next few years."
Brian Shaw, senior biologist at Spey Fishery Board, said: "The Spey Fishery Board was delighted to be able to work with Diageo and its team to bring about this inspiring renovation of the weir and fish pass. We like it. More importantly, so do the fish! The number of spawning redds counted above the weir last autumn was the highest we have recorded.
"We look forward to the Dullan Water fulfilling its potential to become one of the most productive rivers in the Spey catchment."
Diageo is working to achieve Alliance for Water Stewardship certification for its 11 distilleries in the Spey catchment, which recognises a global ambition to nuture and respect the social, cultural, environmental and economic value of freshwater.
The group also has plans to develop its programme of fish pass improvements at its Glen Ord distillery near Inverness later this year.