A foldable box includes a floor and two longitudinal and transverse side exterior walls each lying opposite in pairs and foldable relative to the floor, each longitudinal side exterior walls—including a protrusion at a transverse side end extending toward the transverse side exterior walls when upfolded, limiting foldability of the transverse side exterior walls to the outside. Each transverse side exterior wall including a locking mechanism at the outside of the transverse side exterior wall, including when upfolded, a snap-in element movable in a vertical direction relative to the floor surface, latchable with the protrusion. The protrusion and/or the snap-in element includes contact surfaces, inclined relative to the vertical direction when upfolded wherein the locking mechanism opens against a spring pretensioning when exceeding a predetermined inward force acting upon the transverse side exterior wall.