Peacock spiders have only been found in Australia. Occasionally the species Maratus furvus from China gets a mention. However its inclusion in the genus Maratus is more of a historic artefact. It is a species that is poorly described and nothing in that description indicates that it is a peacock spider.
While some species are known from tropical areas, the majority is restricted to the southern half of the continent. Most species live in the temperate or subtropical southwest or southeast of the continent. Some species prefer coastal areas, even beaches, others can be found on mountain tops, swamps or even desert-like environments.
Most native habitats are suitable for peacock spiders but whether you come across them depends on how hard you search and luck. Most species can be found on the ground or on small twigs strewn on the ground. The best way of finding them is simply to slowly walk along a path and carefully observe what moves. Remember to tread carefully, and if you want to be sure not to kill any accidentally it is probably best to stay on a path. During summer the females will look after their brood, inside a silken chamber (egg sac) they attach to debris. The spiders in these egg sacs don't move when you approach and together with their brood will almost certainly be killed if you step on them.
Best time to find them is in the morning or afternoon. During midday they usually hide.