This is a good question.
And the answer is strictly related to Australian lifestyle and the relationship with alcoholic beverages.
This charming capital “doesn't like to live the night” or better, everything lights up at dawn: in Sydney gyms open at 6am, every person who lives here never wakes up after 8am, meals are quite early and everything switches off very soon to restart the life cycle with enough rest.

During the week nightclubs close before 1:30 am and only on the weekend you can allow yourself to party until 3:00 am and still following the strict laws regarding alcohol intake.
If you want to work in a place that sells alcohol, you must necessarily take a course which certifies that you are aware of some safety rules.
In Australia, alcohol represents a constantly advancing social plague, a reality very different from what we Europeans for instance are used to.
There are therefore very strict laws for the consumption of alcohol and after 10 pm, for example, you can no longer buy alcohol in bottle shops and after midnight the sale of shots, liquors and spirits is prohibited in all bars and clubs around the city.
At barbecues and private parties, you see loads and loads of alcohol, but it is forbidden otherwise to drink alcohol openly in public places in Australia.
The fines are very high for anyone who decides to drink alcohol outside the premises used for this activity.
Minors (under eighteen years of age) cannot drink alcohol and cannot enter the premises that sell alcohol unless accompanied by a parent or a guardian.
At the entrance of each club or bar, there is always a bouncer who checks everyone's identity cards with no exceptions so, if you look 40 or younger, you’ll have to show a document to get in.
Some venues even have a machine able to scan the features of your face and the photo on the document to check if the latter is fake or real.

But are all these rules that try to solve this great drinking issue really effective?
Unfortunately, every weekend we see many people of all ages staggering on the street and feeling sick so it naturally arises some doubts on why in a city so attentive to the sale and consumption of alcohol, this phenomenon represents such a widespread social scourge in continuous expansion.

On a lighter note, the main neighbourhood to go to for nightlife in Sydney is Kings Cross, the place is literally packed with young people on weekends.
Locals nickname it The Cross and this small neighbourhood just a few minutes by train from Sydney's city centre develops around the chaotic Darlinghurst Road and although it appears to be an unsafe and somewhat unkempt area, it boasts a fascinating history.
Kings Cross was once a well-known meeting place for sailors and licensed soldiers while today it is a neighbourhood with two faces: during the day it looks like a fairly sleepy area, where you stop in the cafes of Liverpool Street to sip a coffee while admiring the ancient buildings and the slow comings and goings of people in the street, including many curious tourists.
At night Kings Cross changes its face and attracts young students and backpackers, adults looking for unbridled fun, but also hustlers and disreputable people.
Fortunately, however, the police are present and they patrol the streets of this area to ensure greater safety.
But this neighbourhood is also a place for art and culture, with several theatres, art galleries, clubs, trendy and alternative markets and restaurants to be discovered. All open at night.