Kakaban Island is just 20 minutes boat ride from Sangalaki Island and offers some superb wall diving as well as a landlocked jellyfish lake dive. The island is uninhabited and has been declared a national park.
The Jellyfish Lake is full of four species of jellyfish that have no sting and are therefore harmless to divers. The lake was once a lagoon surrounded by a coral atoll and open to the ocean but over time the coral atoll surrounding the lagoon has been raised up by geological forces, landlocking the lake and it's inhabitants. Although once stingers, the jellyfish have lost there sting due the the absence of natural predators such as turtles. The jellyfish are Mastigias Papua, Aurelia Aurelia, Tripedalia Crystophora and the upside down Cassiopeia Ornate. The 5 square kilometre lake is fed ocean water from underground fissures and is slightly tidal. It's maximum depth is 18m in the middle, the shore line is lined with mangrove. Visibility is 10-15 metres. Other marine life in the lake includes flatworms, sea cucumbers, small fish and a file snake which is also non poisonous.
On the outside of the island are some deep wall dives where the islands limestone cliffs drop vertically into the abyss. Barracuda Point on the southeastern tip of the island is a great places to see swirling schools of chevron barracuda as well as jacks, tuna and sharks. Currents are usually strong at the point. Divers can approach by drifting along either the east or the west wall.
The Blue Light Cave dive starts on the top of the wall at 2m with a descent down a narrow funnel to 20m where it opens up into a large cavern with a bottom at 30m. Divers exit the cave on the wall at 45 metres or deeper at 65m. This is a dive only suitable for experienced divers.
Derawan is the closest to the Borneo mainland so visibility is lower than the other islands, between 5 and 20 metres. That's not really an issue though as most of the diving is macro diving. The house reef beneath the jetty is home to a diverse range of critters including ghostpipefish and seahorse. This is also an excellent place for night dives. At Blue Trigger wall schools of red tooth triggerfish are always seen. At certain times of the year green turtles come ashore to lay their eggs.
Samama is close enough to Sangalaki and Kakaban that it can be dived from there. It is another macro photographers dream destination. Reefs are shallow with maximum depths of around 15 metres. Currents are weak. So dives can be long in duration and the sun light that filters onto the hard and soft corals illuminates them magnificently. Reef life is very healthy with many schools of fish. Look for blue ribbon eels at the edge of the reef. Pygmy seahorse smaller than your fingernail can be found in gorgonian seafans.
Maratua is a large island shaped a bit like the letter C and has a large lagoon protected by a coral reef. Strong currents sweep through the channel into the lagoon and diving the channel should idealy be timed at slack high tide. Drift diving experience is useful here. The fast water attracts schools of jacks, barracuda, tuna and mackeral to the channel entrance. Eagle rays, mantas and sharks are also seen here. On the outside of the reef there are drop offs to 30m with nice soft coral and sponge coverage and large schools of fish.
There is good macro diving inside the lagoon at Nabucco Island. Many different nudibranch species can be seen here as well as frogfish, leaf scorpionfish and mandarin fish.