The trio broke the ice with guests on Friday close to the window at the Gold Coast enclosure.
They weighed just 200g at first but have been growing rapidly, Sea World spokeswoman Katrina Krygger said.
Since hatching they have been fed by both parents, who regurgitate fish.
Ms Krygger described breeding season as an enriching time for the penguins, and said the colony had been trumpeting to show excitement when the chicks chirped.
Their gender will not be known until DNA tests have been carried out.
The theme park is holding a naming competition for one of the Antarctic natives on its Facebook page.
The suggestions so far include Snorkel, Arty and Casey - after the Australian Antarctic Division base.
The $12 million penguin enclosure is home to king and gentoo penguins, which act as a way to teach guests about the impacts of climate change.