I was asked to post the route for this coastal path. The recent extention from Coogee to Navel base isn't well signposted yet, but being new is in excellent condition with some great bush scenary.
You can pick up the path on entering Freo on the Fremantle Bridge. You drop down into Beach St at the new set of lights, a short distance takes you to the entrance to the port where you can pick up the path. This will take you past the Round House, past Little Creatures Brewery, for those that can avoid the temptation. Continue along past South Beach and its Kiosk. On exiting this beach area take as there is often quite deep sand at the entrance to the southern dog beach. Follow the path until you reach road at the old power station, turn left, then 1st right past the Potato Board (rough but little used road). You'll soon pick up the path that will take you to the Coogee Kiosk. Continue on the coastal path past the Caravan park, at the next road intersection, turn left and cross Cockburn Rd. From here is not so well known. Continue south a short distance down Cockburn Rd, turn left into Mayor Rd. Up and over the hill, right at Fawcett. There are a couple of alternative entries back onto the path which takes you along the edge (one a bridge over) Lake Coogee. Cross Russel Rd. Follow the path, for a short distance alongside the road. It then ducks down into bush, alongside Brownman Swamp. The next landmark is Mt Brown with its modern sculptured shading (a good lookout detour), which you may see directly in front if not to your left as the path bends right towards the coast. Follow the path to its end, opposite Navel Base Carvan Park and Kiosk, where there are toilets and a tap.
If you want a longer ride, you can ride about 7kms along Rockingham Rd(this is good if you are ready to prepare yourself for busy fast moving open roads) until you meet Kwinana Beach Rd on the right which takes you along the shore, past the Grain Terminal and some beaches to Rockingham.