The soldiers, who have been battling the Taliban, will be greeted by families and friends at their home base in Beachley Barracks near Chepstow.
More than 550 soldiers from 1 Rifles, many of whom are drawn from the former Devonshire and Dorset Regiment, including several from Exeter, deployed to Helmand province last September, led by Commanding Officer Lieutenant Colonel Joe Cavanagh, as part of 3 Commando Brigade.
Lt Col Cavanagh paid tribute to the soldiers' families and public for their support.
He said: "We remain indebted to you all, we could not have hoped for better support. The battle group has achieved amazing things during this tour — with the Afghan National Army and among ourselves. The Riflemen have been making a difference and know it."
The battle group was responsible for working alongside the Afghan National Army soldiers and officers as their personal mentors, and as liaison officers between the British HQ and the Afghan Brigade.
Working in eight-man teams from remote bases, they lived among the Afghan people, rather than in British bases, for six months of patrols in the local towns and villages and on operations to hunt insurgents.
During the tour, they were involved in what was described as a "stunning success" in the pivotal operation to clear enemy forces from the area around the provincial capital Lashkar Gah, and assisted the ANA to bolster the security around Helmand's second city of Gereshk.
They also provided security across Helmand during voter registration for a forthcoming national elections.
Detachments of Riflemen from two platoons and a Rifles company were employed on a variety of other tasks, such as providing security in the capital Kabul, protecting the southern town of Garmsir, and maintaining the security of the main UK base and airfield, Camp Bastion.
Tragically, eight soldiers from the Rifles Battle Group were killed during the tour, including Serjeant Chris Reed, 25, known as Reedy. He was serving with Exeter-based 6 Battalion The Rifles when he was killed in an explosion while on patrol on January 1.
Sjt Reed had become engaged to Heather Crosby, of Plymouth, on the day he was posted to Afghanistan.
Next month, hundreds of people are expected to line the streets of Exeter for the homecoming march of 6th Battalion The Rifles on April 4.
It will be the first time the battalion, based at Wyvern Barracks in Topsham Road, has been honoured in its own right with an official march through the city.