Australian teenager pleads guilty to plotting bomb attack on Sydney Opera House

A 16-year-old boy, whose identity is protected under Australian law, has pleaded guilty in the New South Wales supreme court to planning a terrorist act over more than a month in 2024. He gave evidence describing how his radicalisation began online.

The teenager told the court he first encountered extremist material on TikTok at age 14, initially drawn to historical content about the Crusades and past empires. Over time, the platform's recommendations shifted toward footage related to the aftermath of the September 11 attacks and Islamic State propaganda, with the content growing progressively more violent.

As his views hardened, he began exchanging messages on the encrypted app Telegram with others who shared an interest in terrorism, telling the court he found the contact interesting because he was trying to connect with a new group of people.

He went on to research targeting the Opera House during the Sydney Marathon, since the landmark serves as the race's finish line and draws large crowds, making it attractive for maximum impact. He said the plan was inspired by footage of the 2013 Boston Marathon bombing, which killed three people and injured more than 500. In online messages, he described deliberately choosing locations crowded with people and tourists, planning to test his methods before an operation, and cited his home country's involvement in conflicts in Iraq and Afghanistan as justification.

Despite the extent of his planning, the teenager said he was only "50/50" on whether he would have gone through with an attack, describing an internal voice that pushed back against the idea.

In court, he expressed remorse and said he no longer holds any extremist views, disavowing Islamic State entirely. His lawyer argued for a non-custodial sentence to allow continued deradicalisation efforts, noting the teen has been under strict home detention bail since November 2024. The prosecution, while acknowledging his candour, argued that a term in custody remains the only appropriate outcome given lingering concerns about his insight. Sentencing is scheduled for 29 October.