Roedd William Hammett yn fab i Mr & Mrs William Hammett, 3 Park Street, Mumbles. Gwasanaethodd fel Preifat 38161, 1st Dorset Regiment a bu farw o effeithiau nwy yng Ngwlad Belg yn 20 oed ar 2 Mai 1915. Fe'i coffawyd ag anrhydedd ar Gofeb Ypres (Menin Gate) ac ar Groglen Goffa y Rhyfel Mawr, Eglwys All Saints', Y Mwmbwls, Abertawe.
Adroddwyd gan y South Wales Daily Post ar 4 Ebrill 1918 - 'Mumbles man Private Edwin Hammett, Welsh Regiment, son of the Oystermouth Cemetery gravedigger has been wounded, and is now in a base hospital. His brother, William Hammett, was killed during the early part of the war'.