Most packing guides are written for American airlines. Here are the rules that actually apply to a Friday flight out of Sydney.
Search "how to pack carry-on only" and nearly every result is written for an American or British airline, with allowances that don't match a single carrier you can actually book here. Australians fly domestically more than almost anyone, and the carry-on backpack rules that matter for a weekend away are Qantas, Virgin and Jetstar's. So this is the local version, with the real numbers, current for 2026 and the change Jetstar is making from February 2027.
The hardest part used to be the simplest thing about it. That is changing for one airline, so here is exactly where each one stands now.
What size backpack is carry-on in Australia?
On Qantas and Virgin Australia, a carry-on backpack can be up to 56 × 36 × 23 cm, wheels, handles and pockets included. Qantas allows up to 10 kg, Virgin 8 kg plus a small personal item. Most travel and laptop backpacks between about 18 and 26 litres fit inside that frame, as long as they hold their shape when packed.
Jetstar is the exception from 2 February 2027. Its free allowance becomes one under-seat bag of 40 × 30 × 20 cm, which in practice means a sling, a small daypack or a tote. A full-size backpack goes overhead only if you add Priority Carry-on.
As a quick guide to our own range:
- Fits overhead on Qantas and Virgin: every backpack we carry, from the Tempo 18L (44 × 30 × 14 cm, 0.55 kg) up to the Transit 26L (48 × 32.5 × 17 cm, 1.1 kg).
- Fits Jetstar's free under-seat allowance: the Urban 4.5L Crossbody Sling (32 × 20 × 9 cm) and the Flow 2.5L Sling. Our backpacks are all over 40 cm tall, so on a Jetstar base fare they need Priority Carry-on.
Measure your own bag at its widest points, packed, not empty. A bag that's in size on paper can still fail the sizer if it bulges.
The one that changed: Jetstar
For years the three big domestic airlines shared one simple carry-on size: 56 by 36 by 23 centimetres. Qantas and Virgin still do. Jetstar is the one to watch, because from 2 February 2027 it is scrapping the old free 7kg carry-on and splitting it in two.
Here is where each airline lands:
- Qantas: one carry-on up to 56 by 36 by 23 cm, up to 10 kg, or two items to 10 kg each on many fares. Free.
- Virgin Australia: one overhead bag up to 56 by 36 by 23 cm at 8 kg, plus a small personal item under the seat. Free.
- Jetstar, from 2 February 2027: your free bag becomes one small under-seat bag, 40 by 30 by 20 cm. To put a full-size 56 by 36 by 23 cm bag (up to 10 kg) in the overhead locker, you buy Priority Carry-on, from $25 one-way on domestic routes and up to around $52 on some international routes, with priority boarding included.
So the old trick of packing light and clearing all three no longer holds for Jetstar. On Qantas and Virgin, a bag built to 56 by 36 by 23 cm still walks straight on for free. On Jetstar you now have a choice: travel light enough for the little under-seat bag, or pay for the overhead. Either way, it still beats checking a bag.
What it costs to get it wrong
The reason the weight matters is what sits on the other side of it. On Jetstar, adding a checked bag at the airport is $120 for the first one, and going over your allowance costs $30 for every extra kilogram. A weekend bag you thought was fine, weighed at the gate and found to be over, can turn into a three-figure fee before you've even boarded. Packing to the limit on purpose is how you make sure the number you pay is zero.
The weekend, packed
Two or three days needs far less than the bag you'd instinctively pack. Here's the whole kit for a weekend. It sits comfortably under 7 kilograms, inside every Australian airline's carry-on weight limit:
- One outfit worn onto the plane, ideally the bulkiest one, jacket and heavier shoes included.
- One spare outfit, plus a second top. Not three of everything.
- Underwear and socks per day, rolled, not folded.
- A single toiletry pouch, travel sizes, kept to the essentials you'll actually reach for.
- One cable and charger pouch, so the bag never gets turned inside out at security.
- The chargers, a book or tablet, and whatever your weekend actually needs. Not what it might need.
Pack to the weight on purpose, and a weekend fits with room to spare.
Roll soft items rather than folding them. Rolling saves space and creases less. Fill the gaps, shoes and corners, with socks and small items. Keep anything you'll want in the air, headphones, a charger, your documents, in the top or an outer pocket so you're not opening the main compartment on a crowded plane.
The bag that makes it easy to comply
A structured bag is what turns all of this from a fiddle into a habit. A soft backpack can technically be within size and still fail at the sizer because it slumps and bulges. A bag built to hold its shape drops into the frame and stays there. The Transit 26L is sized for exactly this, structured enough to pass the sizer and roomy enough for a long weekend, with locking zips as a bonus for the trip itself. For an everyday bag that doubles as a weekender, the Roam 23L holds its shape the same way at 0.9 kg, in four colours.
Flying Jetstar on a base fare from February? Flip the plan. Put the essentials, phone, wallet, passport, charger, in an Urban 4.5L sling that rides under the seat for free, and decide whether the trip is worth Priority Carry-on for the backpack. Our own habit on any airline: wear the sling, pack the backpack.
Get the bag right once and the rest becomes routine. Friday afternoon, Sydney to Melbourne, a bag packed the night before that you already know clears the frame and the scales. You walk on, you stow it overhead, and when you land you walk straight out. No counter, no carousel, no fee. That's the entire point of learning the rules once.
Carry-on backpack questions, answered
Does a backpack count as carry-on in Australia?
Yes. On Qantas and Virgin, a backpack up to 56 × 36 × 23 cm counts as your carry-on. On Jetstar from 2 February 2027, a backpack counts as the free under-seat item only if it's within 40 × 30 × 20 cm. Most aren't, so you'd add Priority Carry-on.
Can I bring a backpack and a handbag?
On Virgin, yes: one overhead bag plus a small personal item. On Qantas, many fares allow two items. On Jetstar base fares from February, it's one under-seat bag only.
Do airlines weigh carry-on backpacks?
Jetstar weighs bags at the gate. Qantas and Virgin rarely do, but the limit still applies. A backpack that's light empty leaves more of your allowance for what's inside.
What size backpack should I buy for carry-on only?
Between 18 and 26 litres covers almost everyone. Go smaller if you travel light or have a shorter frame, and larger if you're carrying a laptop plus a few days of clothes.
