In 1993 he started his international career as a concert soloist in Ukraine.
Since then he has made concerts in countries like Russia, Spain, France, Serbia, China, England, Poland, USA, Sweden, Denmark, Iceland and Finland.
He has been featured as a soloist with orchestras like Norwegian Radio Orchestra, Trondheim Symphony Orchestra, Barratt Due's Chamber Orchestra, Kristiansand Symphony Orchestra, Bodø Sinfonietta, the Norwegian Royal Marine's Symphonic Band and the Royal Norwegian Air Force Band. He has collaborated with musicians as Elise Båtnes, Ole Edvard Antonsen, Christian Eggen, Arne Nordheim, Øyvind Gimse, Ole Kristian Ruud, Stephan Barratt Due and Peter Szilway.
In addition to his career as a soloist and chamber musician, the work of Farmen is very versatile. He tours regularly for the Norwegian Concert Institute and is often used as a session musician in variuos styles