An inexpensive enclosure providing a protected space on a beach, lawn or the like. An inflatable tube forms a wall surrounding a space having an open end, so that a user is shielded from small kicked or thrown material or objects, running pets and the like. The tubular wall has flaps extending from its bottom surface, with pouches or separate tubes which a user fills at the site to hold the enclosure in place. The enclosure may have a floor, and may have attachment portions for removably connecting an extension unit having a floor which extends beyond the open end of the space between side portions of the wall.