Rottnest Island is completely safe. However, Rottnest Island has become notorious for its schoolies week events in November which often take place at night and can get out of hand. There is also a massive police presence on the island during this time, as opposed to the usual 3 officers. Travelling during schoolies week is inadvisable as the peace of the island is briefly shattered.
There are wild dugites snakes on the island which are venomous, however these are only found out in the scrubland and are easily avoidable if you watch where you are treading.
