The US Army on Friday did not specify the nationalities of the soldiers wounded, but said the attacks occurred in southern Zabol province.
"Five coalition soldiers were injured when about 10 insurgents attacked their 10-vehicle convoy with rocket-propelled grenades in the first incident in Zabol on Friday," an army statement said.
In the second attack 62km north of Qalat, three more soldiers were wounded by what seemed to be a booby trap explosion near their Humvee, the statement added.
Two of the injured soldiers were taken to hospital at the Kandahar air base. They were in stable condition and would be transferred to Germany for further treatment.
Zabol is a stronghold for remnants of the Taliban – Afghanistan's former regime which was driven out of power by US-led forces at the end of 2001.
Attacks against coalition troops have been on the rise recently in Afghanistan's south, southeast and east, triggering fears that the Taliban could be out to disrupt the upcoming presidential election in October.