Prince George joined his parents at Taronga Zoo for the opening of the bilby enclosure which is named in his honour.
In their final official engagement in Sydney for this Royal Tour, William and Kate left Admiralty House with their son.
The Duke joked in a speech given when the Cambridges first arrived in Australia last week: "I suspect George's first word might be 'bilby' - only because koala is harder to say. We really look forward to our time here together as a family."
As Prince George's first royal tour draws to a close after 19 days down under, here's a look back at the highlights of the family's trip.
The Duke and Duchess of Cambridge showed off their street credentials at a community youth centre in Adelaide.
The Duke and Duchess of Cambridge visited the Blue Mountains of Australia, where over 100 homes were destroyed by bush fires last year.