Sandra Hanselmann-Kästli took her first piano lessons at the General Department of the Bern Conservatory. Later she studied there at the vocational school in the classes of Albert Schneeberger and her future husband Jürg Hanselmann.
 
In 1985 she finished her studies in Bern with a teacher's diploma. Further studies lead the pianist to Frankfurt, where she studied with Irina Edelstein, and to the Zürich Conservatory, where she took the concert diploma with Verena Pfenninger. Sandra Hanselmann was awarded the Kiefer-Hablitzel-Grant Bern an won the Migros-Award, Zürich, in 1987.