Co-pilot Ann Cole noticed the runway was not clear and steered the aircraft back up in the air. After it circled around for the second landing attempt, the pilots manage to complete the touch-down safely.
The Duke and Duchess of Sussex were joined by around 100 people on board as they travelled from Tonga to Australia. Among their fellow passengers were the couple's staff, police officers and dozens of journalists, who reported on the landing drama via Twitter.
After the aborted landing, the captain Nigel Rosser addressed the passengers, explaining the pilots' decision.
"It was a missed approach. There was an aircraft on the runway that was a little bit slow to roll and unfortunately hadn't cleared the runway. We were too close and the decision was made to abort the landing. So for the second time today you'll get great views of the harbor. We'll get you there safely as soon as possible," the captain said.
The royal couple's tour to will continue following a stop in Australia. On Sunday, the Duke and Duchess of Sussex are expected to travel to New Zealand.