"Trading as" describes the relationship between your legal entity and the brand name customers actually see. It does not create a separate business or a separate address requirement; it sits on top of whatever entity and address already exist.
What is actually happening behind a trading name
A registered business name, the formal term for what most people call "trading as," is linked to an existing ABN, not to a separate registration with its own address [Sleek, sleek.com]. If you are "Jane Smith trading as Riverside Consulting," Jane Smith the sole trader is the legal entity, and Riverside Consulting is simply the public-facing name attached to her existing ABN and address.
Why this matters for your address specifically
You do not register a separate address for each trading name. Every business name you hold, no matter how many, is linked back to the same underlying ABN, and that ABN has one set of address details on the ABR [Sprintlaw, sprintlaw.com.au]. A company can register multiple business names under one ACN and ABN, with all of them sharing the same registered office and principal place of business [Lawpath, lawpath.com.au].
Where the confusion usually comes from
People sometimes assume each "trading as" name needs its own correspondence address, perhaps because each brand has a different look or different customers. In reality, address details are tied to the legal entity, not the brand. If you want different brands to appear to operate from different cities for genuine commercial reasons, that is a separate decision involving multiple virtual addresses, not a requirement that follows automatically from registering multiple trading names.
What stays consistent regardless of how many trading names you have
Your ABN status, your registered office if you have a company, and your principal place of business all sit at the entity level. Update these once, and the change applies across every trading name registered to that entity.
Space Penguin offers virtual addresses in Sydney and Melbourne from $20 per month plus GST, suitable as the one address behind however many trading names you operate under the same entity. Visit spacepenguin.io/virtual-address for current details.