Protective helmet with attachment mechanism for securing accessories

A protective helmet includes a shell, which defines a bottom opening and an internal cavity for receiving the wearer's head. The shell further includes a brim with a central opening defined in the brim. An attachment mechanism for securing an accessory to the shell includes one or more openings defined through the brim on either side of the central opening, wherein each of the openings includes a larger diameter portion and a smaller diameter portion, which are separated by a detent. Each opening receives a respective boss of the accessory, which can be selectively advanced from the larger diameter portion to the small diameter portion of the opening. Furthermore, the attachment mechanism includes a slot defined in and along the edge of the shell, with the slot corresponding with the central opening defined in the brim, such that the slot is configured to receive a projection extending from the accessory.