Leenstra started her career in 1983 playing indoor volleyball for OSV Pegasus Ter Apel.

She also played for Etiflex Ommen, Martinus Amstelveen, Vini Monteschiavo Jesi, Granzotto San Dona, Fiqurella Firenze and Mirabi Iandia Teodora Ravenna.

In 1992 she joined the Dutch senior volleyball team and was selected for the 1992 Summer Olympics in Barcelona, finishing sixth.

She teamed up with Dutch star Rebekka Kadijk, whose sister Debora decided to quit beach volleyball after the 2000 Summer Olympics.

Leenstra's next partner was Sanne Keizer with whom she did not reach any notable results, except a fourth place at a tournament in Montreal.