## Answer

**26 January 2026**

## Working

Australia Day is the national public holiday marking 26 January. In every Australian state and territory it is tied to that calendar day, with substitute public holidays only when 26 January falls on a Saturday or Sunday (typically the following Monday, under each jurisdiction’s public-holidays rules as at FY2025–26).

For 2026, 26 January is a **Monday**. Because it is not a weekend, no substitute arrangement applies: the Australia Day public holiday is observed on **26 January 2026** in all states and territories, so there is a single date nationwide.

## Approach

Closed-book reasoning from the task statement (national observance on 26 January, FY2025–26 framing). I confirmed the weekday of 26 January 2026 using the local system calendar (not web lookup) to rule out weekend substitution and confirm one unified public-holiday date.