Phang Nga dive sites

The Similan Islands are a national park accessible only by boat from Khao Lak or Tab Lamu Pier on the Andaman coast. Day trips depart early morning and take about one and a half hours by speedboat. Liveaboard trips of two to five nights are the preferred option as they allow multiple dives at different sites across the archipelago. The park is open from mid-October to mid-May and completely closed during the monsoon season. No overnight stays on the islands are permitted for divers, making liveaboards the most practical option.

The western sides of the Similan Islands feature dramatic granite boulder formations and stronger currents attracting pelagic life. East of Eden on the sheltered eastern side of Island 7 offers a completely different character, with gently sloping coral gardens in calm water. The hard coral coverage here is among the best in Thailand because the eastern aspect protects the reef from monsoon swells. This makes East of Eden ideal for photography, relaxed exploration, and divers who prefer coral reef scenery over adrenaline dives.

East of Eden is suitable for Open Water certified divers with some experience, though an Advanced Open Water certification is recommended to explore the deeper sections below 18 metres where the largest barrel sponges and leopard sharks are found. Currents are typically mild on the eastern side, making navigation straightforward. The reef slopes from 5 to 30 metres, allowing divers to choose their depth comfort level. Liveaboard operators typically brief this as a relaxed dive suitable for all experience levels.

The standard Koh Bon dive site is the south-facing bay where most day boats and liveaboards anchor. This sheltered bay has moderate conditions and reliable manta encounters at its cleaning station. The West Ridge is the exposed western extension, a granite ridge jutting into the open Andaman Sea. It receives significantly stronger currents, has more challenging conditions, and is dived less frequently. However, the exposed position attracts larger pelagic species including whale sharks and tuna that rarely visit the sheltered bay. Only liveaboards and experienced boat operators typically access the West Ridge.

Whale shark encounters at Koh Bon West Ridge are most frequent from February through April, coinciding with the peak plankton season in the Andaman Sea. The exposed western position of the ridge places it in the path of nutrient-rich currents rising from deep water, creating plankton concentrations that attract filter feeders. Whale shark sightings are not guaranteed and remain a highlight rather than an expectation, but the West Ridge has a higher encounter rate than the standard Koh Bon bay during peak months. Most encounters involve juvenile whale sharks of 4 to 6 metres.