The Aids to Navigation Unit (ANU) of the Marine Department is responsible for providing and maintaining Aids to Navigation (AtoN) in Hong Kong waters according to the guidelines of the International Organization for Marine Aids to Navigation (IALA) to ensure the safe and smooth movement of vessels to and from our port.

ANU maintains over 600 AtoNs, of which about 160 are lighted buoys, 320 are beacons, and 120 are pier lights. The unit has one vessel and one light goods vehicle for daily maintenance. In addition, Government Flying Services provides helicopter service to convey the maintenance team to remote sites such as Waglan Island, Black Point and Ping Chau to maintain the AtoN services.

Traditionally, acetylene served as the fuel source for gas-operated lanterns, which used a pilot flame for ignition. This technology was succeeded by electrically-operated lanterns powered by battery systems and incandescent lamp bulbs. The subsequent automation of Lighthouses eliminated the need for permanent, on-site personnel, transitioning these facilities to remote monitoring and control. Today, over 90% of operational lanterns are powered by renewable solar energy. Furthermore, traditional battery and incandescent lamp bulb systems are being systematically replaced with more energy-efficient LED lanterns.