Abstract: Safety device for quickly locating a drowning victim underwater which essentially includes a hollow cap member open at one end, a threaded spool inside the cap member and containing a water-soluble marking dye, a solid, water-soluble closure member which fits over the cap open end and is adhered to the cap member and may also be adhered to one end of the spool, and a safety pin or similar member to attach the device to a potential drowning victim, the free end of the thread extending outwardly from the cap member with its free end tied to the safety pin or other attaching member which in turn is joined to one of said cap and closure members.