Rottnest Island is a half hour ferry journey from Fremantle and is one of the most popular excursions from Fremantle or Perth. The large numbers of quokkas to be seen are the obvious draw for all the tourists.
If it weren't for these cute looking marsupials (that the early Dutch explorers thought were rats - hence the island's name) I doubt that many would visit the island. The quokka are apparently nocturnal. However there were an enormous number round the tourist area of Thomson Bay, maybe scavenging for food? However feeding or touching the quokkas is an offence incurring a hefty fine.
We took the Grand Island Tour which included coach and train rides to see the Oliver Hill Guns and tunnels from WWII and various scenic lookouts.