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Race IntelligenceBusselton, Australia

IRONMAN 70.3 Western Australia

Know your day before you race it.

Enter four numbers you already train with. You get a likely finish range, target paces and watts, and how I would race this course.

Race day
6 December 2026
Swim
1.9 km
Bike
90 km
Run
21.1 km

Published route evidence. Final 2026 route pending. Checked 14 Sept 2026.

Build my Race Card

Your first range uses conservative assumptions. Add optional evidence to make it more specific. It is calculated in your browser and saved only on this device.

Your numbers
Distance unit
Weight unit
You and this race
Sharpen your range with more detailOptional. Recent swim, bike and run results, equipment and transitions.

Add only the evidence you have. Every control changes a discipline range, its uncertainty, or an execution-risk explanation.

Swim evidence

Replaces the broad pool-to-open-water assumption.

Bike and equipment

These replace broad mass, aerodynamics, tyre, and power-to-speed assumptions.

Run evidence

A recent effort and honest durability/acclimation answers refine the post-bike run.

Race execution

Transition proficiency changes the T1/T2 range and how wet conditions are treated.

What Western Australia actually gives you

You swim one calm loop close to shore at the Busselton Foreshore, ride a fast, flat one-lap route along the coast and through the Tuart Forest, then run two relatively flat loops past the iconic Busselton Jetty and along Geographe Bay. Hold your number on the flat bike and the run stays available.

Show distances in

Swim

1.9 km

Single-loop Foreshore Swim Close to Shore

Setting
the Busselton Foreshore

A calm, single-loop foreshore swim pulled close to shore gives a controllable, honest opening.

Source: 2026 current route

Bike

90 km

Fast, Flat One-lap Route

Setting
the coast and the Tuart Forest

A fast, flat one-lap route through the Tuart Forest removes any terrain reason to hold back, so pacing discipline has to be self-imposed.

Source: 2026 current route

Run

21.1 km

Relatively Flat Two-lap Route

Layout
2 loops
Setting
the Busselton Jetty and Geographe Bay foreshore

A relatively flat two-lap route past the Busselton Jetty rewards legs that didn't override the flat bike.

Source: 2026 current route
Where these course facts come from

These facts come from the organiser’s latest published material: swim, 2026 current route; bike, 2026 current route; run, 2026 current route. They describe the character of the course. They do not confirm the final 2026 route.

How I’d want you to race it

One job for each part of this course. The distance markers tell you when the job changes. The course tells you why.

Swim

Settle at the foreshore

  1. 0–300 m

    The start

    Find clean water early

    The calm, shore-hugging foreshore swim rewards an honest, controlled opening.

    • Seed honestly
    • Settle into rhythm

Bike

Ride the flat by number

  1. 0 km45 km

    Along the coast into Tuart Forest

    The flat is a trap, not a gift

    With no hills to force pacing discipline, it's easy to override on this fast, flat route. Hold your number regardless of how easy it feels.

    • Cap opening effort
    • Fuel early
  2. 45 km90 km

    Back to Busselton

    Protect the run

    Finish planned nutrition and hold effort through the remaining flat miles before the two-loop run.

    • Stay patient
    • Finish planned nutrition

Run

Use both loops past the jetty

  1. 0 km10.5 km

    First loop

    Start controlled

    Let the first loop past the Busselton Jetty feel easy, not fast.

    • Easy first aid station
    • Check posture
  2. 10.5 km21.1 km

    Second loop

    Use what you saved

    Only progress once the first loop has held together.

    • Stay tall
    • Choose the last move late

What I would keep an eye on

There is no useful 2026 forecast this far out. For now, past race dates give us a point of reference. Closer to the race, the forecast will tell us whether the plan needs changing.

Forecast statusToo early for a forecast

A race-day forecast is not meaningful yet; check back closer to the event.

Temperature
13.8–28.1°CDew point centred on 10.3°C
Wind and gusts
14.5 km/hGusts up to 43.6 km/hPrevailing direction SSE
Rain likelihood
Up to 35%Wet-surface uncertainty retained

Historical baseline, 2019–2025 · Open-Meteo historical archive · Updated 2026-09-14.Historical comparison only. This is not a forecast for 2026.

What goes into your range

Your CSS, FTP, weight and run threshold create the first range. Open-water, bike, run and execution evidence can replace broad assumptions. Course data and the historical conditions baseline shape every simulation.

  1. Your numbersCSS · FTP · weight · run threshold
  2. This raceDistance · water type · elevation · exposure
  3. Your Race CardFinish and discipline ranges, with target paces and watts

Confidence is built from four inputs

Athlete evidence
Builds with recent open-water, bike and run efforts
Bike setup
Builds with equipment, mass, aero and tyre detail
Course evidence
Partial while the 2026 route is unconfirmed
Race-week conditions
Historical baseline until a forecast is useful
How the model works

It starts with the targets in your Race Card, then samples the parts of a 70.3 that vary: open-water pace, transitions, bike speed at the planned power, and the drop in run performance after the swim and bike. Repeating that calculation produces a likely range rather than a single heroic number.

The current time calculation uses this race’s published distances, or standard 70.3 distances where none are published, with the available course headings, elevation and exposure evidence. Weather scenarios vary temperature, dew point, wind, gusts, rain and water conditions together. Unknown route detail stays visible as uncertainty rather than false precision.

It is not predicting your exact finishing time, placing, or race-day weather. It answers a narrower question: given the plan and the information we have, what range of day is plausible, and where is the uncertainty coming from?

Confidence is not a permanent “low”. It is recalculated across four separate inputs:

  • Your evidence: consistent inputs and recent race-like swim, bike, and run results.
  • Bike setup: measured or specified aerodynamics rather than a broad prior.
  • The course: verified distance and route character, including elevation and technical sections.
  • The conditions: a current forecast is more useful than a historical comparison.

It starts low when those inputs are broad. It can become moderate or high as the evidence improves. A narrower range means better information, not a guarantee.

If Western Australia is your race

Your range is built on today’s numbers. The months of training before race day decide what those numbers become.

Sources and verification

Course status: Partially verified. The organiser’s descriptions and latest published route profiles are in use. The final 2026 route is not yet confirmed. Last checked 2026-09-14.