A collapsible portable structure which may provide a play environment for children has side walling defining an upright corner region with a free side edge and a canopy which straddles the corner region. The canopy may provide a roof-like cover or at least a partial enclosure. The side walling is formed by at least one continuous loop of a flexible coilable rod supporting a flexible fabric panel. Thus there may be one curved or angular panel, or two adjoining panels or panel sections. The canopy is of flexile fabric and is attached to the fabric of the side walling at a location spaced inwardly from the free edge of the side walling. The canopy is supported separately from the side walling panels by at least one separate pole. A ground sheet may optionally be provided extending across the corner region between the lower edges of the side walling.