How to register for GST once you have your ABN

Nils sells bike accessories out of Rotterdam. His ABN came through last week and he's looking at the GST registration screen, which is short enough to feel like a formality. It isn't. There's one field on it that decides how much money moves, and it isn't the turnover box.

Worth knowing why this is a second step at all, because sellers reasonably expect one registration to cover everything. The ABN identifies the business. GST registration is a separate election that attaches to it, and plenty of ABN holders are not registered for GST — they're under the threshold, or they don't need to be. So the two aren't a package. Having an ABN doesn't register you for GST, and this is exactly where sellers who thought they were done discover they aren't.

The form itself asks four things. Your ABN. The date you want the registration to take effect. How often you'll report — quarterly is the default and what most sellers land on. And whether you account on a cash or accruals basis. Three of those four are quick. The date is not.

Here's why the date matters. Registration doesn't automatically start today. It starts when you say it starts — and if your turnover crossed the A$75,000 line months ago, the obligation began back then, not when you noticed. So the date isn't a preference. It's a finding about your own history, and it needs to match what actually happened.

Which often means backdating. Sellers hear that and flinch, because backdating sounds like volunteering for a bill. Half of that is right: GST becomes payable on sales made from the effective date, and you may not have collected it from those customers. That's a real cost out of margin.

But the other half runs the other way, and it's the half nobody mentions. Input tax credits also start from the effective date. Every dollar of import GST Nils paid at the border in those quarters becomes claimable. He ships four times a year and imports heavily — so for him, backdating pulls a real refund forward at the same time as it creates the liability.

So how do you find the date if you don't already know it? You rebuild the rolling twelve-month figure month by month and find the first month where it cleared A$75,000 — or the first month where the next twelve months were clearly going to. Your marketplace reports will give you the monthly Australian sales; the work is doing it across every channel you sell on, because the test is total Australian turnover, not per-platform. It's an afternoon with a spreadsheet, and it's the afternoon that decides the number.

So the honest way to pick a date is to net the two. GST owed on sales after that date, minus recoverable import credits from that date. For a seller who imports at volume, those numbers can be surprisingly close. For a seller who imports very little, backdating is mostly cost. Same rule, opposite answers — which is why 'just pick today' is bad advice in both directions.

The cash-versus-accruals field, quickly, because it does have consequences. Cash basis counts GST when money moves; accruals counts it when the invoice is raised. Marketplace sellers usually find cash basis simpler, since settlement reports already work that way. Eligibility depends on turnover, and it can be changed later — so it's a decision, not a trap.

One nuance that changes the arithmetic for some sellers: not everything is taxed at ten percent. Some supplies are GST-free, and exports out of Australia are the one that matters here. If part of what you sell from your Australian stock ships back out of the country, that portion is treated differently — it still goes in your total sales, but not in the GST you owe. Sellers running Australia as a regional hub for New Zealand or Asia need to separate those streams rather than apply ten percent across the whole line.

Then lodging it — and here's the part nobody warns overseas sellers about. The ATO's online services for business generally aren't something a non-resident can just sign into: the Australian digital identity they require is hard to get from outside the country. In practice, non-resident registrations go through a registered tax agent, or the slower phone and paper routes. Nils lodged his through an agent — effective date checked, confirmation back quickly, because the identity work from the ABN stage had already done the heavy lifting. Keep that confirmation; it tells you which quarter is your first.

Three things change the moment it's done. Your Australian listings are now GST-inclusive prices, which is a pricing decision you should make deliberately rather than absorb. Your first BAS has a date on it. And your freight invoices become claim-able — the import GST line stops being a sunk cost and starts being something you reconcile.

On the pricing point specifically: Australian displayed prices include GST. So the ten percent doesn't get added at checkout the way US sales tax does — it comes out of the price you're already showing unless you change the price. Sellers who registered early built it in calmly. Sellers who backdate are usually paying it out of margin on sales that have already happened, and pricing forward is the only part of that they can still control.

And if things change — you close the Australian channel, or your stock leaves the country and you drop below the line — registration can be cancelled. There's a final BAS and some record-keeping, and doing it properly matters, because a registration left open quietly accrues lodgment obligations whether or not you're selling.

So that's the decision — and a word on actually getting it done. The rules are public, but the lodgment route mostly isn't a do-it-yourself screen for an overseas seller: without an Australian digital identity the online portal is out of reach, and the remaining routes are slow from the other side of the world. This is exactly what the team at Epic Tax does end to end for overseas sellers — work out the date your obligation actually started, run the backdating arithmetic both ways, and lodge the registration as your registered tax agent, so it's right the first time. General information only, not tax advice.