Three foreign soldiers died in the blast from an improvised explosive device (IED) in eastern Afghanistan Sunday morning, the Nato-led Isaf said in a statement.
The nationality of the soldiers and the exact location of the incident were not disclosed in the statement, as per Isaf protocol.
There was no mention of whether any other soldiers were injured in the blast.
IED blasts are responsible for around half the deaths of foreign soldiers killed in hostile action in the last five years.
Of the 238 soldiers killed by hostile attacks this year, 108 deaths or 45 percent were IED blasts.
Sunday's losses bring to 306 the total number of foreign soldiers killed in Afghanistan in 2012.