Ian has played a major role in the recent success of the Tigers Development XV in the Guinness A League, but competition for places has limited his first team opportunities.
Speaking on his move, Nimmo said: "I am happy that Edinburgh have given me the opportunity to come back home and play rugby. I am keen to prove myself and am looking forward to working hard and hope that I will be able to push for selection."
Edinburgh head coach Lynn Howells said: " Ian will be a welcome addition to Edinburgh squad and will provide much needed height and bulk to the pack."
"Bringing in Ian to the squad further demonstrates Edinburgh Rugby's commitment to developing the best of young Scottish talent," added Edinburgh Rugby's Executive Chairman Alex Carruthers.
Lock. Born: 25.7.85 in Harlow, Essex. Height: 6ft 7in (2.01m). Weight: 18st 4lb (116kg).
Ian played for Scotland at U-18, U-19, and U-21 levels. His U-19 honours included the 2004 IRB world championship in Durban, South Africa, and his U-21 international debut followed when Scotland narrowly lost to France in Bourgoin in February 2005. He went on to play in all five of Scotland's U-21 internationals that year, including the March victory against England at Northampton before continuing his U-21 international career in the world championship in Argentina in June 2005. He played in 18 of Scotland's 20 U-21 matches over the two years, including all 10 in 2006, when he formed an ever-present second-row partnership with James Eddie. Ian is a former pupil of the High School of Dundee. After leaving school, he joined Heriot's and was also a member of the Edinburgh back-up squad in 2004/05, before moving to Leicester Tigers for the 2005/06 season. He joined Coventry in 2006 on a season-long loan deal.