“In WA (Western Australia), it is an offence to:
# buy alcohol (or try to buy it) if you are under 18
# have alcohol with you in a public place (like parks, beach or on the street) if you are under 18
# drink alcohol in a public place, at any age
# send your friend to get alcohol, if you know they are not 18 or older, or
# use a fake ID or give a false age to try and buy alcohol.
You can be fined up to $2,000 if you are convicted of one of those offences.
If you give alcohol to someone under 18 and do not supervise their drinking (even in a private setting), you are committing an offence and could be fined up to $10,000.”
Find more from Legal Aid Western Australia (Australia 2020)