You can easily do this if you stay at the cottages over the water run by locals
All you have to do is sit in the jetty or from your verandah and when you see them, jump into the water and discreetly come from behind them. If you manage to catch up just gently rub his shell and avoid scaring the turtles by pulling him grab his shell so he follows you
Kakaban Island is so special that inside the island is vastly occuppied by a lake which hosts a bunch of stingless jellyfish which you can only find in 2 places: here and in Palau
You can swim in the lake and surrounded by jellyfish :)
When you get bored with jellyfish you can snorkel near the jetty area....there are lots of corals and colourful fishes...one of the best snorkeling spot
and of course if you dive there are many dive spot around the islands
You can visit the sea turtle conservation here and if you're lucky you can see newborn turtles ready to be released to the sea
or sunbathing and swimming in the pristine white beach
Or snorkel and see manta rays if you're lucky
don't miss to visit sangalaki island. it's only about 2 hours from derawan by fisherman's boat and take even less time using the speedboat.
if you're lucky, you'll meet some mantarays. they will swim around your boat. we met like 10 of them! if you spend a nite on this island (no hotel on the island at the moment) you will see turtle laying their eggs on the beach every night. they're endangered species, so please don't disturb them.
The lake was originally the lagoon of an atoll, formed by corals over a period of two million years. As a result of movements in the earth's crust the coral reef was raised above the sea level, trapping 5 km2 of seawater within a 50 meter high ridge, effectively creating a landlocked marine lake.
The organisms found in the lake are originally seawater species such as marine algae, sea anemones, jellyfish, sponges, sea cucumbers, crabs, and several small fish species. Seawater, which seems to enter the lake through small cracks and crevices in the surrounding reef rock, is diluted with rain water, to produce a brackish water environment. Over thousands of years the inhabitants of the lake have adapted to their unusual environment. No large channels or connecting caves have been discovered, so no larger animals have been able to enter or leave the lake for thousands of years. Marine scientists are still trying to solve the mystery of how the isolated and fragile lake ecosystem supports the requirements of its plant and animal communities. Only one other similar lake ecosystem is known; it is found on Palau in Micronesia, about 1000 km east of the Philippines.
Most def you should go snorkeling with them stingless jellyfish. It's really fun to swim among floating jellyfish.
There are several sand dunes near Derawan Island which you can visit during low tides.
A nice place to take pictures :)