Louis Soonius is widely admired for his paintings of sunny, colourful beaches with figures and for his harbour views, seascapes and townscapes.

He drew his inspiration from the city and outlying areas of The Hague, where he lived his entire life apart from one brief interruption.

Louis Soonius also made frequent trips to nearby Katwijk, and to the cosmopolitan resort of Scheveningen, where he painted children and bathers enjoying themselves on the beach in summer. He was a member of the city's art society, the Haagsche Kunstkring.