Provided herein is a collapsible bulk-sized shipping box made of corrugated plastic. The rectangular box comprises four joined sidewalls, wherein left and right sidewalls are bisected by vertical fold lines allowing the sidewalls to be collapsed inwards. Bottom flaps also extend from the bottom of respective sidewalls and hinge inward about a fold line to provide a bottom side of the box when in use or fold flush with the sidewall when collapsed. The front wall of the box comprises a door flap that hinges inward and outward about a fold line. In addition, a door retaining puck attached to an outer surface of the front wall and configured to resist the door flap opening outward but deflect under application of sufficient force thereby allowing the door flap to open outward completely and provide access to the interior of the box.