The official South Korean news agency says North Korea has told international authorities it will carry out a controversial satellite launch between 4 and 8 April.
Pyongyang had earlier confirmed the launch, but given no date.
North Korea says it has given the necessary world bodies the information for the safe navigation of planes and ships ahead of the launch of what it calls an experimental communication satellite.
The South and the US believe Pyongyang could be preparing to test-fire a long-range missile and have warned it not to go ahead with the launch.
But North Korea insists it is preparing to send up a satellite, not a missile.
It has said any attempt to shoot it down will result in war.