MelasLithos
Contributor
You may want to specify Kalimantan as East Kalimantan & the best time to dive is from March to October, as mentioned here: Dive Maratua Island
There are no good dive sites in the south & west of Kalimantan. The north side is Borneo, belongs to Malaysia. You already mention Layang-Layang & Sipadan. In fact Sipadan is just a few miles north of Maratua Atoll, East Kalimantan, which includes Kakaban (the only sting-less jellyfish lake available for visit currently, as the one in Palau is closed for rejuvenation from El Niño & Chinese invasion. Sharks are already almost gone, now the stingless jellyfish is the new target by the Chinese), Derawan, Sangalaki, Nunukan & Nabucco.
Thanks for the info. I've edited the file.