Size
The Australian Terrier is larger on average: about 8 kg (18 lb) as an adult, against 5.1 kg (11 lb) for the Yorkshire Terrier.
Shedding
Their coats shed differently: the Australian Terrier holds loose hair until it is brushed or clipped out, the Yorkshire Terrier sheds through the year.
Grooming
The Yorkshire Terrier needs more grooming, daily brushing, where the Australian Terrier needs a brush once a week.
Temperament
They differ most on affection (Australian Terrier: affectionate on its own terms; Yorkshire Terrier: a lap or leaning dog) and on loyalty (Australian Terrier: bonded to its family; Yorkshire Terrier: sticks close to its people).
Alike
Both are rated the same on independence: decides for itself.