A child containment system has a child containment structure with a bottom and a perimeter wall surrounding the bottom. A bassinet has an infant support surface and a surrounding wall around the infant support surface. The bassinet can be mounted to the child containment structure with the infant support surface elevated above the bottom of the child containment structure. An infant support unit can have a frame, a bed supported by the frame, and legs that extend from one end of the infant support unit to the distal second end. The infant support unit is configured for use in a first operational mode in which the infant support unit at least partially positioned within the child containment structure with the bed overlying the bassinet's infant support surface, and with a portion of the legs contacting the bassinet's infant support surface.