An important highway called Itäväylä, serving Helsinki's eastern suburbs, goes through the island, cutting it in two halves.

[2] So-called Brändö Villastad was founded in 1907 by a group of businessmen, architects and engineers outside the city of Helsinki, including Allan Granfelt.

Their aim was to form on 250 acres of the barely inhabited island a town consisting of modern villas for middle-class families.

[3] The architect Lars Sonck, who was a member of the company, drew up the town plan for the area in 1909, the town-planning principles of which were inspired by Austrian planner Camillo Sitte's influential book Städtebau as well as Garden City Planning derived from England, with Sonck striving to give as many house owners as possible direct access to the sea from their plot, while public buildings were placed further inland.

Nowadays, Kulosaari is also noted for the location of a significant of purpose-built foreign embassy buildings, including those of China, India, Vietnam, Lithuania, Slovakia, Romania, Columbia, Iraq and Iran.