Marmion Avenue is a 40-kilometre (25 mi) arterial road in the northern coastal suburbs of Perth, Western Australia, linking Trigg in the south with Yanchep in the north.

Marmion Avenue is part of State Route 71, from the southern terminus to Yanchep Beach Road, continuing on from West Coast Highway.

It commences in Trigg, traveling generally parallel with the Indian Ocean coastline, and the other north-south arterials Mitchell Freeway and Wanneroo Road, through mostly residential areas and some undeveloped land north of Currambine, and terminates in Yanchep.

[5] The speed limit for most of Marmion Avenue was previously 80km/h but was updated in February 2023 with new policies stating the maximum speed through traffic signals is 70km/h Marmion Avenue starts as a four-lane dual carriageway as a continuation of West Coast Highway, at the traffic light controlled intersection with Karrinyup Road in the City of Stirling.

Marmion Avenue continues north through residential areas, intersecting with Ocean Reef Road, Hodges Drive, Shenton Avenue and Moore Drive, and passing by Currambine Central Shopping Centre, before intersecting with Burns Beach Road.

Until the early 1980s, the road was a two-lane single carriageway connecting the coastal suburbs of Marmion and Mullaloo Beach.

Marmion Avenue was finally duplicated to its terminus in 2001, with the last portion being the empty stretch between Burns Beach Road & Quinns Rocks.

In 2000 and 2001, Reid Highway was extended as a two lane road from its terminus at Mitchell Freeway to Marmion Avenue, providing another link to the east.

[7] After delays due to disagreements at State Government level about what route the road should follow, Marmion Avenue was extended further north to Yanchep and opened to traffic in November 2008.

[8][9] On 1 July 2010, fixed red light and speed cameras were installed at the Marmion Avenue / Hepburn Avenue intersection to fine people who run red lights and speed, so the number of road deaths in Western Australia can be reduced.

[14][15][16][17][18] During 2017, works were undertaken to widen Marmion Avenue to a four-lane dual carriageway between Lukin Drive and Butler Boulevard.