"The more things change, the more they stay the same," he said.
Coroneos said that internet penetration had increased from 22 per cent to 82 per cent during his time with the association.
"So what was then the area for enthusiasts has now become a mainstream communications medium," he said.
IIA chairman Bruce Linn said Coroneos had lead the IIA to evolve from a narrow base representing largely internet service providers to "a diverse, influential and highly respected organisation" in his 13-year tenure.
"We have punched far above our weight, due in large measure to Peter's passion, commitment and breadth of understanding," Linn said.
Coroneos warned that the industry faced three major challenges in the future: internet blackouts brought about by the government such as those in Egypt, natural disasters like the Queensland floods compromising internet access and the potential psychological barrier to e-commerce if users grow to distrust the internet because of the rise of online fraud.
"I'm very concerned that we don't lose trust and confidence in the user base," he said. "The internet is a bit more fragile than we'd care to admit."
Linn said the IIA Board would now begin a national recruitment program to search for Coroneos' replacement.