An erectable play structure for children including one or more enclosures or pods (10, 11, 12) which may be interconnected by one or more access tunnels (14) the whole structure being formed predominantly from a non-self supporting material thus to be collapsible for storage and adapted to be connected to an air pump (18) whereby the internal pressure within the structure may be slightly in excess of ambient pressure thus to maintain the structure in an erect condition. One or more access ports (15, 16) and/or blanking plates (17) may be provided in each enclosure to allow or prevent access to or exit from the enclosure. The access ports (16) are constructed such that after passage there through they resume a closed condition to resist escape of air therethrough. Hook and loop fasteners or the like are used to attach the enclosures, tunnels and access ports together in assembly of the structure.