Photo: Kino / Unsplash
Hin Daeng & Hin Muang
Hin Daeng and Hin Muang are two remote submerged pinnacles in the far southern Andaman Sea, roughly 55-70km offshore south of Koh Lanta and near Koh Rok. Hin Daeng ("Red Rock") just breaks the surface and drops away in soft-coral slopes and walls; Hin Muang ("Purple Rock") stays fully submerged and forms Thailand's deepest wall, an elongated pinnacle from about 12m down past 60-70m, cloaked in purple soft coral. The draw is big animals in blue water: oceanic (giant) mantas, seasonal whale sharks, grey reef sharks, leopard sharks and schooling trevally and barracuda over dramatic soft-coral drop-offs. These are advanced sites — deep, exposed and often swept by strong, shifting current, with no shallow reef to shelter on if conditions turn. Manta and whale-shark odds are best February to April, when plankton blooms draw the big animals but also cut visibility. Access is the real cost: there is no quick day trip. Boats run 1.5 hours by speedboat or 2.5-3.5+ hours each way by larger dive boat from Koh Lanta, and many divers reach them by liveaboard. The sites sit inside Mu Ko Lanta National Park, which closes for the southwest monsoon — diving is a mid-October-to-mid-May affair only.
What makes it special
- Hin Muang is Thailand's deepest wall — an elongated submerged pinnacle dropping past 60-70m, sheathed in purple soft coral
- Among Thailand's most reliable sites for oceanic (giant) mantas; a documented aggregation area recognised as an Important Shark and Ray Area
- Seasonal whale sharks and resident grey reef sharks over dramatic soft-coral drop-offs in open blue water
- Often combined on the same trip with the nearby Koh Ha caverns and pinnacles
Price range
$$–$$$
Trip length
1–5 days
Diver level
Advanced open water
Trip type
Day trip, Liveaboard
Price is per person for a typical trip, excluding international flights ($$ $2,000–4,000 to $$$ over $4,000).
Hin Daeng/Hin Muang day trips from Koh Lanta typically run about 4,500-6,500 THB (roughly $125-185) for three dives on a larger boat, gear and park fees extra; speedboat trips cost more. Multi-day southern-Andaman liveaboards that include these sites plus Koh Ha and the Similans run higher. Mu Ko Lanta National Park fees are paid separately in cash: about 400-500 THB park entrance plus a diving surcharge, confirm current amounts at booking.
Best time to dive
- Current
- Strong
- Water temp
- 28–30°C (coldest Jan, warmest Mar)
- Visibility
- 10–30m — Often 20-30m in the calm, dry season. Drops to 10-15m during the February-April plankton blooms that bring mantas and whale sharks — the big animals and the best visibility rarely coincide.
- Getting there
- Moderate — Reachable but with some friction: a 2.5h overland transfer, a 2h boat crossing.
- Experience
- Advanced-only in practice. These are deep, exposed blue-water pinnacles with strong, shifting currents (sometimes downcurrents), surface waves and no shallow reef to retreat to. Operators expect Advanced Open Water and good buoyancy; the deep walls of Hin Muang reward disciplined depth and gas management, not exploring past limits.
Nearest airports
- KBV — Krabi International Airport (Main arrival airport; about 2-2.5 hours by road (and bridges/ferry) to Koh Lanta, where boats depart. Sites are a further open-water crossing south)
- HKT — Phuket International Airport (Alternative international airport; roughly 3-4 hours by road and ferry to Koh Lanta, or a boarding point for some southern-Andaman liveaboards)
Permit required
The sites lie inside Mu Ko Lanta National Park; park fees are collected in cash by operators at check-in, separate from the trip price.
Mu Ko Lanta National Park foreign-adult entrance is roughly 400-500 THB plus a per-day diving surcharge, paid in cash. Amounts vary by operator and change; confirm at booking.
Marine life
Sightings are never guaranteed — the bars show typical likelihood by month.
| Month | Likelihood |
|---|---|
| January | occasional |
| February | peak season |
| March | peak season |
| April | peak season |
| May | rare |
| June | occasional |
| July | occasional |
| August | occasional |
| September | occasional |
| October | occasional |
| November | rare |
| December | occasional |
Hin Daeng and Hin Muang are among Thailand's most reliable oceanic manta sites — a recognised aggregation area — with best odds during the Feb-April plankton season. Still never guaranteed.
| Month | Likelihood |
|---|---|
| January | occasional |
| February | peak season |
| March | peak season |
| April | peak season |
| May | occasional |
| June | occasional |
| July | occasional |
| August | occasional |
| September | occasional |
| October | occasional |
| November | occasional |
| December | occasional |
Reef mantas also visit the pinnacles alongside the larger oceanic mantas, most often Feb-April.
| Month | Likelihood |
|---|---|
| January | rare |
| February | occasional |
| March | occasional |
| April | occasional |
| May | rare |
| June | rare |
| July | rare |
| August | rare |
| September | rare |
| October | rare |
| November | rare |
| December | rare |
Whale sharks are reported year-round but realistically rare; sightings cluster in the Feb-April plankton bloom. Many trips see none.
| Month | Likelihood |
|---|---|
| January | commonly seen |
| February | commonly seen |
| March | commonly seen |
| April | commonly seen |
| May | commonly seen |
| June | commonly seen |
| July | commonly seen |
| August | commonly seen |
| September | commonly seen |
| October | commonly seen |
| November | commonly seen |
| December | commonly seen |
Grey reef sharks are among the more reliable large animals here, patrolling the deeper walls of both pinnacles.
| Month | Likelihood |
|---|---|
| January | occasional |
| February | occasional |
| March | occasional |
| April | occasional |
| May | occasional |
| June | occasional |
| July | occasional |
| August | occasional |
| September | occasional |
| October | occasional |
| November | occasional |
| December | occasional |
Dogtooth tuna and rainbow runners pass through the blue water off the pinnacles.
| Month | Likelihood |
|---|---|
| January | commonly seen |
| February | commonly seen |
| March | commonly seen |
| April | commonly seen |
| May | commonly seen |
| June | commonly seen |
| July | commonly seen |
| August | commonly seen |
| September | commonly seen |
| October | commonly seen |
| November | commonly seen |
| December | commonly seen |
Barracuda school over the drop-offs at both sites.
| Month | Likelihood |
|---|---|
| January | occasional |
| February | occasional |
| March | occasional |
| April | occasional |
| May | occasional |
| June | occasional |
| July | occasional |
| August | occasional |
| September | occasional |
| October | occasional |
| November | occasional |
| December | occasional |
Leopard (zebra) sharks rest on sandy patches around the pinnacles and Koh Ha, most often in the calm dry season.
| Month | Likelihood |
|---|---|
| January | commonly seen |
| February | commonly seen |
| March | commonly seen |
| April | commonly seen |
| May | commonly seen |
| June | commonly seen |
| July | commonly seen |
| August | commonly seen |
| September | commonly seen |
| October | commonly seen |
| November | commonly seen |
| December | commonly seen |
Dense schools of snapper and other reef fish cover the soft-coral walls.
| Month | Likelihood |
|---|---|
| January | commonly seen |
| February | commonly seen |
| March | commonly seen |
| April | commonly seen |
| May | commonly seen |
| June | commonly seen |
| July | commonly seen |
| August | commonly seen |
| September | commonly seen |
| October | commonly seen |
| November | commonly seen |
| December | commonly seen |
Trevally school and hunt along the walls; giant trevally are common among them.
| Month | Likelihood |
|---|---|
| January | occasional |
| February | occasional |
| March | occasional |
| April | occasional |
| May | occasional |
| June | occasional |
| July | occasional |
| August | occasional |
| September | occasional |
| October | occasional |
| November | occasional |
| December | occasional |
Whitetip reef sharks are seen on and around the pinnacle walls.
Dive sites
Worth knowing before you book
- No quick day trip: 1.5 hours by speedboat or 2.5-3.5+ hours each way by larger boat from Koh Lanta, and the crossing over open water can be rough.
- The park closes for the southwest monsoon — realistically diveable mid-October to mid-May only, with the sites shut roughly 16 May to 15 October.
- Advanced-only: deep, exposed pinnacles with strong, sometimes downward currents and no shallow refuge if conditions turn.
- Mantas and whale sharks are the headline but genuinely unpredictable — best odds February-April, and many trips see neither.
- The plankton that brings the big animals also cuts visibility to 10-15m, so the best-animal window is often the worst-visibility window.
Sources & last checked
Checked July 2026
This is a researched draft, not yet human-verified. The seasonality and logistics are drawn from the sources below — confirm specifics (permits, fees, closures) with an operator before you book.
- Hin Daeng / Hin Muang Diving, Andaman Sea — Thailand — Dive The World
- Hin Muang & Hin Daeng — Important Shark and Ray Area — IUCN SSC Shark Specialist Group (ISRA)
- Mu Ko Lanta National Park — Wikipedia
- Diving Hin Daeng Hin Muang Dive Site from Koh Lanta — Phoenix Divers Koh Lanta
Note on the data: Distance from Koh Lanta is reported inconsistently across operators (55-70km; 1.5h speedboat vs 2.5-4h larger boat); access figures are representative, not surveyed. Coordinates are the Hin Daeng seamount position with Hin Muang ~200m away; bounding box is drawn around both pinnacles. Park-fee amounts vary by operator and are flagged for verification against a current DNP source. Closure dates for the Hin Daeng/Hin Muang sites are reported as roughly 16 May-15 Oct (some sources 1 Jul-30 Sep, others mid-May to mid-Oct); operating months set conservatively to the calm Nov-Apr diving window. Water temperature interpolated from a published 27-30C seasonal range. Water temperature: The Andaman stays warm 27-30C year-round, warmest February to April; monthly bands are interpolated from that published seasonal range, not measured per-month, and cold upwellings can drop a single deep dive on Hin Muang several degrees below these surface figures. Access: Fly to Krabi (KBV), ~2-2.5h by road and ferry to Koh Lanta, then a long open-water crossing south — about 1.5h by speedboat or 2.5-3.5+h by larger dive boat; also reachable by southern-Andaman liveaboard. Independently verified 2026-07-20 (confidence medium).