About 500 soldiers from the 1st Battalion The Royal Irish Regiment, based at Clive Barracks in Tern Hill, are in the country to provide security, training and support.
They will be based around three main places – the airport, centre of Kabul and in the national army academy.
At the weekend the Royal Irish took part in a 'transition of authority' ceremony.
The regiment has taken over from the 2nd Battalion The Royal Gurkha Rifles.
The Royal Gurkha Rifles have been in Afghanistan since April as part of Operation TORAL, a force protection mission for NATO staff based in Kabul.
Since deploying earlier this year, they have been keeping busy as part of NATO's Resolute Support Mission, providing enduring support to the Afghan Government.
Their primary role has been protecting UK and NATO mentors supporting the training of Afghan National Army (ANA) Officer Cadet.
As the Shropshire soldiers arrived in Afghanistan, they were told that communication would be key to their mission.
Lieutenant Colonel Graham Shannon addressed soldiers as the Royal Gurkhas formally handed over the role of Kabul protection Unit to the Royal Irish.
The ceremony included officers and soldiers from a number of nations.
Captain Andre Genillard of the 2nd Battalion The Royal Gurkha Rifles took down the Gurkhas battalion flag accompanied by one of the Royal Gurkha Rifles battalion pipers.
Captain Wes Brown of 1st Battalion The Royal Irish Regiment raised the Royal Irish battalion flag, accompanied by Lance Corporal Warner on the pipes.
Lt Col Shannon said the main job of the regiment will be to provide security and support.
He said: "My team will continue the relentless pursuit of excellence to drive this mission forward. The importance of the mission is clear, communication is key – we need to use that skill to build relationships with our partners, those we protect, and with each other.
"As we meet and forge bonds with our NATO partners over the coming months it is worth reflecting that we are no strangers to each other – serving alongside each other as far back as Bastogne and Normandy."
Commander British Forces Afghanistan and Commander Kabul Security Force Brigadier Ian Thomas said: "The Gurkhas have certainly improved the situation in Kabul.
"The Royal Gurkha Rifles have proved to be great 'team mates', working exceptionally well with our allies and partners here in Afghanistan. I wish the Royal Irish the best of luck during their time in Kabul."
The Royal Irish has carried out three tours of duty in Afghanistan previously in 2006, 2008 and 2011.
Two years ago the regiment took delivery of new types of armoured vehicles after officially changing its focus from an air to a ground assault organisation.
Until 2014 it mainly roped or dropped into action from helicopters, but then officially changed its designation to a light-armoured vehicle based group.
The changes were part of the ongoing UK-wide restructuring plan known as Army 2020.
Since 2014 the regiment has been known as a light protected mobility battalion operating from a range of new vehicles, including the Foxhound.