Etsy does not require an ABN. The ATO's "in business" test does.
There is no Etsy-specific rule forcing you to register anything. The real question is whether the ATO would say you are "carrying on a business" -- and most ongoing Etsy shops meet that bar well before they feel like a real business to the person running them.
From $39, the ABR's own ABN fee is $0. Same service as our main ABN application page, this page is just about the Etsy-specific question.

The four factors that actually decide it
Not your category, not your revenue on its own -- these are what the ATO weighs when deciding whether your Etsy shop counts as a business.
Profit-making intention
Are you pricing to make money, not just to cover materials as a one-off? Intent to profit is the first thing weighed, and most Etsy sellers who set prices with a margin already clear this.
Repetition and regularity
A single sale of an old item is not a business. Restocking, listing new products, and selling on an ongoing basis looks like one -- and is treated like one.
Businesslike manner
Deliberate pricing, marketing, branding and record-keeping all point toward "in business," even if your Etsy shop is still small and part-time.
The category does not matter. Handmade goods, vintage finds, print-on-demand and digital downloads are all judged by the same test. Whether you are "in business" comes down to your conduct and intent, not what's in the listing.
The honest "just trying it out" answer
If you genuinely list a few things with no real profit motive -- clearing out old craft supplies, testing an idea with zero marketing -- you may not need an ABN immediately. That window closes fast. The moment you start restocking, pricing deliberately, or reinvesting proceeds into more stock, you have crossed into "carrying on a business" whether or not it feels that way yet.
Trading without an ABN when you're supposed to have one creates real friction before it creates a legal problem: you can't invoice properly, and some wholesale suppliers will not deal with an unregistered buyer at all.
What changes at $75,000
GST registration becomes mandatory once your GST turnover reaches $75,000 in a 12-month period. Below that line it's optional -- worth doing anyway if you have significant GST credits on materials and supplies, otherwise safe to skip until you're closer to the threshold.
Once registered, you charge 10% GST on taxable Australian sales and lodge a Business Activity Statement (BAS) on a schedule the ATO sets. Digital downloads and overseas sales have their own nuances here -- worth a real accountant's input once you're near the threshold, not a guess.