At the outbreak of the First World War, Sonia and Robert were on holiday in the Basque town of Hondarribia in northern Spain. They decided not to return to Paris and spent the next seven years travelling within Spain and Portugal.
In Portugal the couple were welcomed as members of the international modern avant-garde and developed a number of projects with local artists who shared a common preoccupation with abstraction.
Sonia also looked at more traditional subjects, such as her series depicting the market in Minho. At this point her work still balanced figuration and abstraction, with circular forms that blur the boundary between the two.
Her fascination with advertising and graphic design was still evident. In her designs for the journal Ararat 1917, letters are combined with geometric shapes and a reduced palette of colours, while the catalogue of her 1916 exhibition at the Nya Konstgalleriet, Stockholm incorporates a series of abstract self-portraits.