To begin with, not all shops have the same opening hours. There are always exceptions and we don’t know if there are certain regulations for them.
In general, shops are open from 9 am to 5 pm from Monday to Friday, but not all shops have the same opening hours on Saturday. On Sunday shops in the city shopping malls and some shopping centers are open between noon and 5 pm.
There are also long shopping days which means that the shops in the city are open on Friday until 9 pm, whereas the shops in the suburbs are open on Thursday until 9 pm. But as we said, not all shops are open and probably the shop you want to go into is closed anyway on these days.
It’s rather a mystery to us how some of the shops can survive, because the normal office hours are also from 9 to 5. The only possibility to shop for office workers is on the long shopping days or on the weekend. But maybe there are enough retired people and housewifes living in Perth who can shop during daytime.
Many supermarkets are also only open from 9 pm to 5 pm. Some supermarkets have extended opening hours which means they are open until 10 pm. In Subiaco near our house is a small, god-sent supermarket which is open 24 hours, 7 days a week. This supermarket saved us from starving more than once.
