Net Creek begins from the south end of Rib Lake in Best Township. From there it flows about 3 km (1.9 mi) south into Petraut Lake. It then flows 1.50 km (0.93 mi) to the south-southwest into Duncan Lake where it runs another 0.67 km (0.42 mi) south-southwest into Ferguson Lake. At the south end of Ferguson Lake the creek then flows south-southwest 0.08 km (0.050 mi) into Net Lake. From the south end of Outlet Bay, Net Creek flows south-southeast into Cassels Lake. The creek has an approximate elevation of 300 m (980 ft) and has a length of about 15 km (9.3 mi).
Net Creek is part of the Ottawa River drainage basin, a large area covering much of eastern Ontario and western Quebec where water drains into the Ottawa River. After Net Creek flows into Cassels Lake, the water enters Rabbit Lake, which is drained by the Matabitchuan River. The Matabitchuan River then flows into Lake Timiskaming where the water eventually enters the Ottawa River.