​Leon Frei (2005) is a double bassist from Winterthur, Switzerland. He began playing the double bass at the age of five, with his early musical interests initially rooted in folk music.

Over the years, he developed a growing connection to classical music and, as a teenager, became a member of the Winterthur Youth Symphony Orchestra. Through his musical environment and various professional engagements, he eventually discovered a strong fascination for jazz, which has continued to deepen through performing in diverse jazz ensembles and has had a lasting influence on his bass playing.

Since February 2024, Leon Frei has been the double bassist of the Swiss lineup of Claude Diallo Situation, led by pianist Claude Diallo, with whom he has performed in countries including Greece and Germany. He is also the bandleader of The Leon Kings.

In addition to his work as a double bassist, he is the bassist of the Balkan band FiddleJammer since 2020, which won the Band-it! music competition in 2024.

In recent years, Leon Frei had the opportunity to perform with several renowned artists and ensembles, including Bruno Spoerri, Tupac Mantilla, Rafaele Lunardi and the Swiss Youth Symphony Orchestra.

He is currently doing his Bachelor’s degree at the Jazzcampus Basel, where he studies with teachers such as Larry Grenadier and Bänz Oester.