Nicoline Alt started playing the oboe at the age of eleven and enrolled four years later at the Royal Conservatoire in The Hague, where she studied with Frank Minderaa and Ali Green. Upon graduating with honours, she went on to study with Klaus Becker in Hanover.
From an early age, Alt proved to be a talented oboist, winning first prize at various competitions, including the 1987 National Competition of the Foundation for Young Musical Talent in the Netherlands and the 1988 Edith Stein Competition (later called the Princess Christina Competition). In June 1990, she won the Expressivity Competition at the Royal Conservatoire in The Hague.
After playing in the National Youth Orchestra of the Netherlands for four years, Nicoline was a member of the European Union Youth Orchestra from 1990 to 1994. She was subsequently appointed first oboist of the Nederlands Balletorkest.
Alt joined the Royal Concertgebouw Orchestra as second oboist in January 1998. She also gives regular chamber music concerts.