It is the central section of State Route 2, which continues north as Mitchell Freeway to Clarkson, and south as Forrest Highway towards Bunbury.

It commences at the northern end of the Narrows Bridge, Perth, continuing south from the Mitchell Freeway, and terminates at the Pinjarra Road interchange at Barragup, where it then transitions to Forrest Highway.

The slowest section was from South Street to Canning Highway, with an average travel speed of 24 kilometres per hour (15 mph).

During the afternoon peak, the worst segment was southbound between Manning Road and Leach Highway, with a 31 kilometres per hour (19 mph) average speed.

The Kwinana Freeway continues south, with the suburbs of Manning and Salter Point to the east, and Canning River to its west.

The freeway passes by Aquinas College, 1.5 kilometres (0.93 mi) south of Manning Road, and reaches the Mount Henry Peninsula after another 600 metres (2,000 ft).

The freeway travels through the suburb for 450 metres (1,480 ft)[13] to Cranford Avenue, a half-diamond interchange with northbound entrance and southbound exit ramps.

Halfway between these interchanges, Parry Avenue crosses the freeway via an overpass, connecting the suburbs of Bateman and Bull Creek.

[1][2] A free-flowing combination interchange, 800 metres (2,600 ft)[13] south of Farrington Road, connects the Kwinana Freeway to Roe Highway and Murdoch Drive.

Here collector-distributor lanes form on both sides of the freeway, which now passes lower density lots in Cockburn Central and the industrial section of Jandakot.

After a further 600 metres (2,000 ft) the full-diamond interchange with Beeliar Drive is reached, whereupon the collector-distributor lanes merge back into the freeway.

The freeway progresses through swampy rural land for 3.4 kilometres (2.1 mi),[16] passing by Lake Balmanup in Wandi on its way to the diamond interchange at Anketell Road.

The Kwinana Freeway continues south along the edge of Jandakot Regional Park, near to The Spectacles Wetlands, reaching Thomas Road after another 2.4 kilometres (1.5 mi).

[16] The Mandurah rail line deviates from the freeway median 1 kilometre (0.62 mi)[16] north of the interchange, thereafter travelling south-west towards Rockingham.

After 5 kilometres (3.1 mi)[16] the freeway leaves the Perth Metropolitan Region, and encounters the next interchange with Lymon Road and Mandjoogoordap Drive.

The interchange included a complicated bridge design, which began at Judd Street, crossed over the freeway, and curved down to join the northbound carriageway.

[23]: 69  A botanical report on the extension found that no unique species or ecological unit would be under threat from the proposal,[23]: 59  and the Swan River Conservation Board[note 2] had no objections.

The freeway was initially planned to terminate at Leach Highway, but was extended as far as South Street, at the request of the Melville City Council.

The council wanted the extra length of freeway to alleviate congestion on its local roads, and contributed $600,000 to expedite the construction.

These included the establishment of a protected strip of vegetation alongside the freeway, and the preservation or enhancement of remnant wetlands under threat from urban expansion.

The EPA's report concluded that the alignment was not ideal from an environmental standpoint, but recognised the social importance of constructing the freeway, which would facilitate development of the area.

Intersections were used to avoid delaying the extension, as Main Roads Western Australia considered the $30 million cost for interchanges to be prohibitively expensive.

[17]: 394 In 1988, the State Planning Commission proposed defining a reservation for the extension of the Kwinana Freeway to the southern edge of Perth Metropolitan Region, north-east of Mandurah.

The northern and southern sections of the route were predetermined by factors including existing and proposed developments, power transmission lines, the location of wetlands and the Serpentine River, and required setbacks from an explosives depot at Baldivis.

Other areas with specific plans included topsoil management, drainage, construction (covering dust, noise, and vibrations), foreshores, and both Aboriginal and European heritage.

[38] The route bypasses Mandurah by taking traffic around the eastern side of the Peel-Harvey Estuary prior to joining the existing dual carriageway on Old Coast Road, reducing the journey time from Perth to Bunbury.

[17]: 360–61 In 1999, the state government announced that a two way bus transitway would be built in the Kwinana Freeway median, to link Perth's Esplanade Busport with the Murdoch station at South Street.

By May 2013, all major construction works had been completed, including a pedestrian underpass at South Street, a new carpark and access road for Murdoch railway station, and noise walls.

[56] The project aims to increase the freeway's reliability, efficiency, and safety, as the current two-lane configuration is subject to a large proportion of heavy vehicles and severe peak hour congestion.

The City of South Perth considers the ramp a "major priority"[64] that would increase its road network connectivity, reduce traffic congestion, and improve commuter safety.