The Ministry of Defence said the men, from 1st Battalion The Mercian Regiment, which is attached to The Royal Gurkha Rifles Battle Group, died in small arms fire in a battle with the Taliban.
The firefight with insurgent forces happened in the Nahr-e Saraj district of Helmand.
Their deaths takes the number of British troops who have died since 2001 when the mission in Afghanistan began to 292.
Lieutenant Colonel James Carr-Smith, from Task Force Helmand, said: "It is with deep sorrow I must inform you that two soldiers from 1st Battalion The Mercian Regiment, part of 1st Battalion The Royal Gurkha Rifles Battle Group, were killed by small arms fire yesterday afternoon in Nahr-e Saraj, Helmand.
"They will be sorely missed and we will remember them."
Their families have been told.
