Farmers have lifted an 18-month ban which has stopped the SAS from training on 43,000 acres in mid Wales.
The SAS trains new recruits in mid Wales
Imposed as a protest against hunting laws, members of the Elan Valley Tenants' Association changed their minds after meeting army chiefs.
The land affected stretches from Rhayader in Powys to Cwmystwyth, near Aberystwyth.
In October, Exercise Pilgrim's Progress was diverted away from mid and south west Wales after farmers banned troops.
Brigadier Iain Cholerton, Commander 160 (Wales) Brigade, said he was delighted by the decision after meeting the farmers.
Robert Lewis, chairman of the tenants' association, said the army told his members that their land was crucial for Special Forces' selection training.
Mr Lewis said: "We listened to the powerful case provided by the brigadier for the need for training in the Elan area and having listened decided that we did not wish to disadvantage soldiers.
"Despite the refusal by the government to listen to our case to differentiate between hunting for sport and genuine pest control, which has always been a vital part of making hill farming viable, farmers are still willing to allow the special forces to exercise over their land.
"Our protest has been successful in raising awareness of this issue and we now need to resume the excellent relationship we have always had with the army."
He added that the arrangement, which sees the army train on the land free of charge, would be kept under review.
Brig Cholerton said: "This area represents some of the toughest land available in the country.
"Almost every soldier you see on your television screens, and many you won't see, in whatever theatre, will probably have trained on a Welsh hillside and the people of Wales and especially the Elan can be hugely proud of this contribution to our operational effectiveness."
At a meeting with the Farmers' Union of Wales in October, Brig Cholerton urged farmers to drop their opposition to soldiers, including the SAS, training on their land.