You will find Menjangan Island in the north west of Bali and although it can take some time to get here, it is more than worth it is you want to visit the Menjangan National Marine Park.
As well as trekking on the island the main reason to come here is for the diving and you will find a plethora of underwater delights such as coral reefs and colorful fish.
There is also a good chance of seeing other sea creatures such as turtles, octopus, crabs, and rays.
