This is the Beach Scene by Hilaire-Germain-Edgar Degas. It's one of four beach scenes he painted in around 1869 when he travelled to the coast of northern France. Notice how other objects are scattered around - two parasols, a basket and a summer bonnet - as well as a family group leaving the shoreline in the background.
Degas was heavily influenced by Japanese prints during this time, adopting many aspects of their composition and subject matter. The woman combing her hair is a motif that appears in several Japanese prints, and it's also featured here.
The painting itself is oil on paper, mounted on canvas, which gives it a unique watercolour-like effect. It was painted using an unconventional technique at the time, where most of the oil was removed with blotting paper and diluted with turpentine.
Degas' contemporaries were also drawn to beach scenes in resorts like Trouville, but he's taken some liberties with composition and figure placement compared to other works from this period.
Beach Scene hangs in The National Gallery on Trafalgar Square, London — free to enter. Point your phone at any artwork there and audioguide.london plays a free audio guide in six languages — no app download needed.