Kammala jumla mai zuwa: A lokacin yakin Somme a watan Satumbar 1916, Dalton ya shiga cikin fadace-fadace masu zub da jini a lokacin yakin basasa.
Yaƙin Ginchy, wanda sama da 'yan Irish 4,000 suka mutu ko suka ji rauni. Daga cikin wadanda suka mutu akwai Tom Kettle, tsohon dan majalisa na kasa da kuma aboki na mahaifin Dalton da Emmet. An ba Dalton lambar yabo ta Soja saboda halinsa a yaƙin. Bayan haka an tura shi zuwa Bataliya ta 6, Leinster Regiment, kuma aka aika zuwa Salonika sannan Palestine, inda ya umurci kamfani sannan ya kula da makarantar 'yan bindiga a El Arish. A cikin 1918 an sake tura Dalton zuwa Faransa, kuma a watan Yuli ya zama kyaftin, yana aiki a matsayin mai koyarwa.