The two men, Will Saunders and David Burgess, were protesting Australia's part in the war in Iraq. They were sentenced to nine months' periodic detention, along with A$150,000, which they paid in two installments of A$40,000 and today's final installment of A$70,000.
The light sentence handed down to Saunders and Burgess provoked the passage last November of a new law, which would give people who intentionally or recklessly damage the opera house a jail term of up to seven years.
Burgess told the ABC that he was relieved to have paid his debt, but that he didn't regret his actions. "I think it was an action that had to be done," he said. "I think it spoke the feelings of Australia."