what's the legal age to sit in the front seat

In Australia, there isn’t a magic birthday for the front seat—it hinges on age brackets and whether the car has more than one row, and no, being “tall for their age” doesn’t trump the rules.

Under 4 years: must not sit in the front if the vehicle has two or more rows; in a single-row vehicle they may ride up front only in an approved child restraint (avoid rear-facing with an active airbag).

Ages 4–7: front seat is only allowed if every rear seat is already occupied by children under 7, and they must use an approved booster/child restraint that fits correctly.

7 years and over: may sit in the front with a properly adjusted seatbelt (or booster if needed), though the back seat remains the safer spot.

Rules are state-based but largely harmonised—check your local road authority for any quirks, and slide that seat back from the airbag like you actually read the manual.