The Calgary-based company says start up activities have begun at its oilsands base plant north of Fort McMurray, Alta.
Suncor also expects its MacKay River extraction site will be producing by the end of this week.
It has already restarted its Firebag extraction facility, 120 kilomitres northeast of the base plant.
Suncor says it has moved more than 4,000 employees and contractors back into the region, which was evacuated because of the devastating fires that swept through the area earlier this month.
It says an additional 3,500 people working for Suncor will return this week to support its operations.