The popular domestic flight up to 60% cheaper from Sydney's new airport

Sydney's newest airport is weeks away from taking off, and early fare data reveals one popular domestic route could soon cost you up to 60 per cent less.

As Western Sydney International (Nancy Bird Walton) airport prepares for its maiden passenger flights on Sunday, October 25, the big question for travellers is simple: will switching between Sydney and Western Sydney airports actually save you money?

We teamed up with Skyscanner to crunch the numbers - and some of the price gaps are dramatic.

Airlines are already discounting flights from Western Sydney airport. But it's still early days and only a handful of airlines have signed on with the airport so far.

Singapore Airlines, Air New Zealand and Vietjet have all partnered with Western Sydney to provide international services, and Qantas and Jetstar have signed up to deliver domestic routes.

But the new airport will likely attract more airlines in the future, and as this happens, we can expect more introductory discounts to come online.

Justin Brownjohn, senior manager at RMIT Aviation Academy, says we can expect to see "a period of heavy marketing and discounting" as Western Sydney takes off.

"This is seen in most multi-airport cities with new routes - even today, Avalon is priced more competitively than Tullamarine - though the catchment in Western Sydney is very different to Bellarine Peninsula," Brownjohn tells Explore.

But this might not remain long-term.

"In time as its connectivity grows and schedules increase, there is a very real likelihood that the two markets will price similarly on comparative routes."

Now for the flight prices. We looked at flights from Western Sydney International versus Sydney Kingsford Smith for February 2026, and the results were varied.

For the overwhelming majority of routes, Western Sydney was cheaper, though the difference ranged from a few dollars to hundreds of dollars.

Skyscanner data from August 19 showed the average cost of a one-way economy flight in February 2027 from the legacy Sydney airport to Singapore, flying with Singapore Airlines, was $723, compared with a slightly cheaper $720 from Western Sydney.

Data sourced on the same date for the same month comparing Air New Zealand flights to Auckland found it would cost $294 from Sydney or a $30-odd cheaper from Western Sydney at $263.

One international route was a whole lot cheaper. If you're flying to Vietnam, you're in luck. Flying Vietjet to Ho Chi Minh City during February cost on average $439 from Sydney and $219 from Western Sydney.

But the biggest percentage difference was on Australia's most popular domestic route, flying between Sydney and Melbourne.

Skyscanner data accessed on August 20 for April 2027 - Qantas' first month in operation at the new airport - found Qantas flights were $326 from Sydney, compared to only $127 from Western Sydney - a whopping 60 per cent cheaper.

The discount wasn't so generous to Brisbane, where Qantas prices for the same month from Sydney and Western Sydney were very similar at $138 and $127 respectively.

Looking at Jetstar in February, flying to Melbourne didn't offer up a very large difference in prices, which sat at $87 from Sydney and $75 from Western Sydney.

One route was actually more expensive on Jetstar. Flying to Brisbane cost $81 from Sydney or $84 from Western Sydney.

Canberra-bound passengers wouldn't have been up for much of a difference, with the route costing $279 from Sydney and $264 from Western Sydney.

Likewise, Hobart was also much the same, coming in at $121 from Sydney and $115 from WSI.

Skyscanner Australia Travel Expert, Jarrod Kris, says airfares are dynamic and can change based on factors including demand, capacity, competition and airline pricing strategies.

"As Western Sydney International becomes more established and more services are added, we would expect prices across both airports to continue to move in response to these factors," Kris tells Explore.

The key benefit for travellers is greater choice.

"Having another airport serving Sydney gives travellers more options when comparing routes, airlines and fares, and that additional competition can ultimately be positive for value," Kris says.

While Western Sydney has plenty of prospective passengers, RMIT's Justin Brownjohn notes that airlines are launching with light schedules to experiment and test new infrastructure.

"Over time, schedules will undoubtably be increased and this improved schedule will command higher fares in the longer term," he says.

Some prices might even become more expensive from Western Sydney.

"Singapore Airlines will launch flights at the end of 2026 with a schedule that is currently impossible at Kingsford Smith due to the curfew - over time, I envisage this flight to potentially command a higher fare than others at Kingsford Smith as it will open new connectivity over Singapore that currently require a longer a transit time," Brownjohn says.