The wreck was found 40 metres deep, approximately 7.8 nautical miles south of Rottnest Island, by divers investigating a sonar anomaly on 1 January 2025.

A historic vessel

Built in 1925 for the Royal Netherlands Navy, K XI was one of the first submarines designed for long-range patrols in the Netherlands East Indies (NEI). During World War II, the vessel was relocated to Fremantle, Australia, where it played a role in Allied submarine operations in the Pacific theatre.

The submarine gained historical significance in March 1942 when it rescued 13 survivors from the Australian warship HMAS Yarra (II), which had been sunk by a Japanese naval force. Following the war, K XI was decommissioned and stripped of equipment before being scuttled at sea in September 1946.

Discovery and survey

The wreck was located by WreckSploration in collaboration with the Western Australian Museum. Divers confirmed the submarine's identity by comparing structural features with historical records. Photogrammetry imaging has mapped key elements, including torpedo tubes, hatches, and remains of the conning tower.

“The wreck is remarkably well-preserved, with much of the pressure hull intact beneath the seabed,” said maritime archaeologist Patrick Morrison, who led the study. The site is being incorporated into the Atlas of Shipwrecks of Historical Interest off the Coast of Australia.

Protection and future research

As a Commonwealth-protected wreck, K XI is safeguarded under Australia’s Underwater Cultural Heritage Act 2018. While recreational diving is permitted, removal or disturbance of artefacts is strictly prohibited.

Future research will focus on 3D site modelling and remote sensing surveys to uncover additional wreckage in the area. The discovery of K XI adds a crucial chapter to the history of Dutch naval operations in World War II and Fremantle’s role as an Allied submarine base.