NBN's speed leap, one year on

When NBN Co pushed its most popular wholesale speed tiers several times higher, the question hanging over the program was whether the underlying network could carry the load. A year of data from the Australian Competition & Consumer Commission suggests it mostly could — with a couple of caveats that have shifted the bottleneck closer to the living room.

The program, called Accelerate Great, went live on September 14, 2025, and made millions of Australians on fixed-line fibre to the premises (FTTP) or hybrid fibre coaxial (HFC) connections eligible for substantially faster speeds.

What the upgrade actually changed

The headline change was on the NBN 100 tier, also marketed as Home Fast, which rose fivefold from 100Mbps to 500Mbps. The NBN 250 Home Superfast tier was tripled to 750Mbps. Home Ultrafast kept its near-gigabit downloads but had its maximum upload speed doubled to 100Mbps.

NBN Co also introduced Home Hyperfast, its first residential multi-gigabit tier, with wholesale speeds of up to 2,000/200Mbps over FTTP and 2,000/100Mbps over HFC.

By the outlet's own framing, this was one of the biggest changes to the NBN since the network's rollout began — a wholesale re-rating of the tiers most households actually buy.

The percentage that looks like a dip

Comparing ACCC measurements before and after the launch produces a counterintuitive result. The commission's September 2025 report, drawing on measurements taken the previous May, found fixed-line NBN services were delivering an average of 102% of advertised download speed during busy evening hours.

The next round of testing began on September 14 — the same day the new tiers launched — and measured upgraded services only after they had moved to their faster speeds. Average busy-hour performance slipped to 100% of plan speed, and by the ACCC's final report in June 2026, based on March measurements, it stood at 99.4%.

Those figures only look like a decline because the percentage is relative to what customers pay for. Before the upgrade, 102% of a 100Mbps plan meant roughly 102Mbps. Afterwards, 100% of a 500Mbps plan means around 500Mbps — a far larger number hiding behind a smaller-sounding percentage.

How the faster tiers held up in practice

The tier-by-tier numbers support that reading. Immediately after launch, FTTP customers on the new NBN 500 tier averaged 102.5% of plan speed during the busy 7pm to 11pm window — a little over 500Mbps. HFC NBN 500 connections averaged 97.4%, or roughly 487Mbps, while NBN 750 services over FTTP averaged 97.3%, equivalent to around 730Mbps.

In other words, rather than buckling under a sudden surge in available bandwidth, the fixed-line network generally delivered close to the full speed of the new plans during the hours when demand peaks.

The 500Mbps tier became the default

NBN Co itself has deemed NBN 500 the most popular tier, and the ACCC's testing sample shows how quickly that happened. Before Accelerate Great, NBN 100 dominated the monitored higher-speed connections with 530 services in the May 2025 sample. The commission's June 2025 Wholesale Market Report counted just over 2.1 million active NBN 100 connections at that point.

In the first testing period after the upgrade, there were already 462 NBN 500 connections and 112 NBN 750 connections, while NBN 100 services had fallen to 124 in the sample. The wholesale report showed active NBN 100 connections dropping to just over 780,000, while active connections of 100Mbps and faster — not currently split by download rate — jumped from around 695,000 to just over 2.4 million.

By March 2026, the ACCC was monitoring 624 NBN 500 services. There are now over 3 million active connections at 100Mbps and faster, while 100Mbps connections have dipped further to just over 713,000. The mainstream high-speed NBN connection had shifted from around 100Mbps to around 500Mbps in a matter of months.

Reliability did not appear to pay for the speed

The extra bandwidth also didn't seem to come at the cost of widespread reliability problems. The ACCC's final report recorded an average of 0.16 outages lasting more than 30 seconds per fixed-line service per day, which it said was consistent with previous reports.

That matters because Accelerate Great sharply increased the bandwidth available to many households without an obvious corresponding spike in outages or a collapse in evening performance — the two failure modes a program of this size might have produced.

Where the new weak link sits

The data also shows that not every connection has been able to use the extra speed. Before the upgrades, around 3% of monitored fixed-line services were classified as underperforming — a service that "rarely or never attains plan speed". That rose to around 4% immediately after Accelerate Great and reached 5.6% by the final report.

Underperforming connections were historically associated overwhelmingly with fibre to the node (FTTN), where the final stretch of the connection still runs over copper. After the new tiers arrived, the ACCC began seeing a greater proportion of underperforming FTTP and HFC services too.

That doesn't necessarily mean FTTP or HFC were struggling with the added bandwidth. The ACCC identified customer-side equipment as one possible cause, including network hardware and cabling incapable of supporting the higher speeds. Moving from 100Mbps to 500Mbps makes parts of a home network that previously weren't a limitation much more important — an older or lower-spec router, for instance, can become the weak link and stop you seeing the full benefit over Wi-Fi.

What the ACCC's sample can and can't show

There are caveats attached to the figures. The ACCC's Measuring Broadband Australia program uses a sample of volunteer households rather than every NBN connection in the country, and the make-up of that sample changed between reports.

Even with those limits, the overall picture is difficult to read as anything other than positive: eligible users were given substantially more bandwidth, the majority of monitored services kept delivering around their advertised speeds, and the network did so without an obvious deterioration in reliability — against a jump that raised the headline download speed of one of Australia's most popular products fivefold.

Why it matters for households still on older plans

For anyone still sitting on an NBN 50 plan with an eligible FTTP or HFC connection, the year of data suggests there is now headroom worth considering. The move to NBN 500 is a far bigger step than going from 50Mbps to 100Mbps.

• NBN 500 busy-hour average over FTTP immediately post-launch: 102.5% of plan speed
• NBN 500 busy-hour average over HFC: 97.4% (around 487Mbps)
• NBN 750 busy-hour average over FTTP: 97.3% (around 730Mbps)
• Average fixed-line outages longer than 30 seconds: 0.16 per service per day
• Underperforming services: around 3% before, around 4% immediately after, 5.6% by the final report
• Active connections at 100Mbps and faster: from around 695,000 to just over 2.4 million, and now over 3 million

The extra bandwidth won't make every web page load five times faster, but it can make a considerable difference in homes where several people stream, game, download large files, use cloud services or work from home at once. As Australian households connect more devices and consume more data, those benefits are only likely to become more relevant — and the ACCC's figures suggest the fibre network is largely ready to carry them.