NEW YORK—A man on a personal watercraft who became stranded in a New York bay easily breached Kennedy Airport’s security system by walking undetected through two runways and into a terminal.

The New York Post reports that the 31-year-old man swam to a Jamaica Bay shore and then walked past motion sensors and closed-circuit cameras of the airport’s state-of-the-art Perimeter Intrusion Detection System. The $100 million system is meant to safeguard against terrorists.

The man climbed an 8-foot-tall perimeter fence and made his way to Terminal 3.

He approached a Delta Airlines worker, who alerted authorities.

The Port Authority of New York and New Jersey is investigating. The agency says it plans to meet with the security system’s maker this week.

The man was charged with criminal trespass.