Koh Bida Nok

The small island-rock of Koh Bida Nok is located two kilometers south of Phi Phi Island. The island's diameter is no more than 100 meters. The island is uninhabitable, but it is one of the most beautiful diving spots. If you go diving at the Phi Phi Islands on a day trip from Phuket, it's highly likely that this will be your first dive site.
This site is rarely visited by people who have never dived before or lack an Open Water (or higher) certification. However, the average depth is around 6 meters, but it's worth it.
The dive begins in the small bay of Bida Nok. The depth in the bay ranges from 1 to 5 meters, but divers spend a lot of time here. The bottom is covered with coral reefs among which many diverse fish swim, ranging from small clownfish to large barracudas. But the main attraction of this bay are the reef sharks that inhabit it.
Reef sharks are not dangerous to humans, and I would even say they fear humans more. Reef sharks grow up to 2.5 meters, but those are considered very large individuals; on average, they are about 1 meter long. They are very fast and shy, so to see them, you need to constantly look around. As I mentioned above, they usually pose no threat to humans, but that doesn't mean you should try to touch them; after all, sharks have sharp teeth, and if they feel threatened, they might bite.
Heading left out of the bay, you can reach depths of 30+ meters. Descending along the wall, it's not uncommon to encounter large schools of fish moving synchronously, mesmerizing the diver's gaze. This phenomenon is called murmuration – the synchronized movement of schools of fish or flocks of birds. Swimming alongside or even among the fish, you can lose track of time, but the main thing is not to forget to check your air gauge)
Going deeper and deeper, there's a chance to encounter a sleeping leopard shark or stingray, and even octopuses.
Coral lovers will be satisfied with a dive at this site. Besides the gorgonians, Acropora, and other types of hard corals widely found in the Andaman Sea, here you can also find soft corals, bubble corals, and sea anemones.
This dive site is one of my absolute favorites. Regardless of the conditions, whether it's calm, clear water on a sunny day or murky water with strong currents, you can always see something new and interesting.