Stage 4 of the 2026 Santos Tour Down Under was a hilly stage that took place on .

The stage started in Brighton and finished in Willunga Hill, starting at with an expected finish at (average speed of 42 km/h).

The total distance of the stage was 175.8 km. The stage included 0 categorized climb(s) and 0 intermediate sprint(s), and had a total elevation gain of 1959 m, and a total descent of 1588 m.