On 22 August, the regiment moved out by truck for Brest, a strongly fortified German-held port city. The regiment completed its march by the afternoon of 23 August at an assembly area near Ploudalmézeau, northwest of the city. The 116th, the first to arrive, sent the 3rd Battalion to "a forward assembly area one mile northeast of" Saint-Renan on 24 August. From the forward assembly area, the battalion patrolled the line of departure for the 29th's attack, a southeast-facing line around four miles northwest of the city. For the attack, the 29th was positioned on the right flank of VIII Corps. The regiment moved up to the line of departure on the night of 24–25 August, beginning the attack at 01:00. The 116th advanced south in column of battalions with the 115th Infantry on its left. Its 3rd Battalion initially faced little resistance, and by 04:00, the 1st Battalion was tasked with capturing the high ground at Guilers and Keriolet by attacking on the 3rd Battalion's right. German resistance increased throughout the day, and the regiment dug in for the night. During the next two days, German oppositions stiffened further, and the regiment was relieved by the 115th so that it could flank the German positions by using a natural ridgeline towards Brest.