Derawan is an island city in East Kalimantan, Indonesia
There is no direct international flight to Derawan. The only one international airport in East Kalimantan is Sepinggan at Balikpapan. From Balikpapan we could choose to go to Tarakan or Berau with smaller plane. But there is no flight to Derawan.
So if you choose to go to Tarakan, you must continue the journey with 3 - 4 hours across the sea by speed boat. If you choose to go to Berau, you must go to Tanjung Batu first by land transportation (it's about 2 hours long from Berau) and then take 30 minutes journey by speed boat to Derawan.
If you want to go by land transport from Balikpapan, you will take about 750 km to reach Tanjung Batu and then take 30 minutes journey by speed boat to Derawan. It is a long and hard way. It could take 16 - 24 hours long because of the condition of the road. The path is Balikpapan - Samarinda - Bontang - Sangatta - Muara Wahau - Berau - Tanjung Batu.
Note there is no ATM on the island and changing money is not guaranteed. You need to bring all your cash with you. There are ATM s in Berau.
We can dive or snorkel at Derawan island or for deep sea diving we could go to Maratua island. Famous spot for snorkeling is Manta Spot, we could see Manta fish there near Sangalaki island.
We can see big fish (shark) and sea turtle if we dive at Maratua or Derawan island.
There are many hotels in Derawan. The largest one is Derawan Dive Resort managed by PT BMI. Others hotel managed by local citizens.
If you want to stay on another island there are two resorts on and near Maratua island. Nabucco resort and Paradise resort. These two resorts are rather upmarket. If you want to go for a cheaper option on Maratua Island, go for Maratua Guesthouse (www.maratuaguesthouse.com). It's located right on a deserted beach and has a wonderful terrace for relaxing and eating great (even Western) food.
Kakaban island is a conservation island for jellyfish, so nobody lives here. Sangalaki island is for sea turtle conservation. Only NGO people live here. Swimming with manta rays is a highlight of visiting Sangalaki Island.