- The species exhibits a single breeding season; mating occurs between June and October, with some local variation taking place between different populations across its range.
- Outside the mating season, the platypus lives in a simple ground burrow, the entrance of which is about 30 cm (12 in) above the water level. After mating, the female constructs a deeper, more elaborate burrow up to 20 m (66 ft) long and blocked at intervals with plugs (which may act as a safeguard against rising waters or predators, or as a method of regulating humidity and temperature).[58]
- The male takes no part in caring for its young, and retreats to his year-long burrow.
- It lays one to three (usually two) small, leathery eggs slightly rounder than bird eggs.