Its area of operation was to the front at Guillemont and Ginchy. It was part of the assault which took Guillemont on 3 September 1916 along with the Connaught Rangers. After the initial attack on Ginchy failed, it was left open to a counter-attack, then withdrawn to recover from its losses. It returned on 7 September 1916 with 200 men for the next attack on Ginchy. With inadequate cover, by 9 September 1916 it was inflicted with heavy casualties and was unable to bury its dead. The other battalions of the 16th (Irish) Division captured Ginchy. The Division was then transferred northwards to the Ypres salient. The 8th RMF was on rotating trench engagements with continual casualties up to 7. November 1916. It was disbanded with 21 officers and 446 other ranks on 22 November 1916, and its personnel drafted into the 1st RMF (Regular) Battalion which had returned from Gallipoli, just three weeks after the disbandment of the 7th RMF in Macedonia.