Observatory is a shallow artificial reef and wreck site located off Middle Island, Australia. With depths ranging from 2 to 6 metres, it is well-suited for beginners and snorkellers. Access is by boat only, and the site is situated 15 kilometres from the shore. Currents are generally mild, though diving during slack tide is recommended to maintain visibility, which fluctuates between 5 and 30 metres. Species recorded around this area include hawksbill sea turtles, ornate wobbegongs, epaulette sharks, nudibranchs, and various reef fish such as rock cod, wrasses, and coral trout. Divers should remain aware of boat traffic and the presence of jellyfish, which are more common from November to April.

Middle Island offers a shallow reef environment with depths ranging from 4 to 6 metres, averaging 5 metres. This site is accessible only by boat and is suitable for beginners, though conditions vary. Visibility typically ranges between 7 and 16 metres. Divers and snorkellers should be aware of moderate currents and changing conditions in Keppel Bay. Hazards include jellyfish, sharks, and sharp coral. Marine stingers are more frequent between October and May, and strong winds can create rough seas. Death adders have been observed on the island itself. Always consult your skipper regarding current direction and local conditions before entering the water.

Cullen Island, located at Middle Island, offers a versatile reef environment suitable for both shore and boat entries. The site features a wall and reef topography with depths ranging from 1 to 30 metres, averaging 4 metres. Conditions are generally mild, making it accessible for beginners. Visibility typically spans 10 to 30 metres. Divers and snorkellers should be aware of boat traffic and the presence of jellyfish, particularly between November and April. Stinger suits are recommended during these months. Facilities available at the site include equipment rental, a cafe, toilets, boat charters, guided tours, and parking.

Monkey Beach on Middle Island offers shallow reef diving and snorkelling in a protected bay. With depths ranging from 1 to 8 metres, the site is well-suited for beginners. The topography features staghorn coral formations that provide structure for the reef. Conditions are typically calm, though currents can strengthen. Visibility generally spans 7 to 16 metres. Divers and snorkellers can encounter wobbegong sharks, turtles, nudibranchs, sweetlips, and coral trout. Access is available via shore or boat, with facilities including parking, toilets, and a cafe nearby. Be aware of potential boat traffic and marine stingers, including Irukandji jellyfish, particularly between October and May.

Hideaway is a reef site located off Great Keppel Island, Australia, offering a quieter experience than other regional locations. The site features depths ranging from 6 to 25 metres, with an average of 18 metres, making it suitable for intermediate divers. Access is by boat, and divers should be mindful of sharp coral and rocks when entering the water. Visibility typically spans 10 to 30 metres, though currents can shift from mild to stronger flows. Species recorded around this area include ornate wobbegong, rock cod, wrasses, batfish, golden trevally, yellow boxfish, crabs, humbug dascyllus, lemon damsel, snails, and hard coral.

Butterfish Bay on Great Keppel Island offers a shallow reef environment suitable for beginners. Depths range from 2 to 5 metres, with visibility typically between 10 and 25 metres. The site features hard corals and plate coral formations. While currents are generally mild, they can strengthen, and it is recommended to dive at high slack tide. The bay is protected from south-easterly winds, providing calm conditions. Species recorded around this area include hawksbill sea turtles, ornate wobbegongs, epaulette sharks, and various wrasses and rock cod. Divers should be aware of boat traffic and the presence of jellyfish, with thin lycra suits recommended for protection.

Shelving Beach, also known as Big Peninsula or Secret Beach, is a sheltered reef site located off Great Keppel Island. The reef structure extends from the surface to a maximum depth of 12 metres, making it suitable for beginners. Divers and snorkellers encounter branching and massive corals, blue barred parrotfish, butterflyfish, and nudibranchs. Green sea turtles and stingrays are frequently spotted, with reef sharks occasionally passing through the area. Conditions include mild currents and water temperatures ranging from 20C to 28C. Access is by boat, and visitors should remain aware of boat traffic when surfacing. Visibility can shift noticeably, so checking local reports before heading out is recommended.

Wreck Beach is a reef dive site located off Great Keppel Island, Australia. The site features a reef structure composed of hard corals, situated at depths between 10 and 15 metres. It is suitable for beginners due to the moderate depth and mild currents. Access to the site is by boat, and divers should remain vigilant regarding boat traffic during surface intervals and ascents. Visibility at this location is variable and can change daily, so it is recommended to check local conditions before departure. Divers should monitor their depth and time throughout the dive and use a surface marker buoy for safety.