A child safety seat includes a seat base having shell body, and a support leg connected with the shell body. The support leg includes a tubular segment, a support portion, a fastener connected with the tubular segment and the support portion, and a cushioning structure disposed adjacent to the fastener, wherein the cushioning structure is configured to block displacement of the fastener so that the support portion is locked in position relative to the tubular segment, and to deform or break as a result of a displacement of the fastener into the cushioning structure when a substantial force is applied that forces the tubular segment to move relative to the support portion.