Phi Phi Diving Is Set by the Park, Not by the Season

Six limestone islands, and a reef that stops at 8 to 10 metres

Phi Phi is six limestone islands, about 40 kilometres southeast of Phuket and about 30 kilometres west of Krabi, standing in a large shallow bay that a 2010 coral study describes as nowhere deeper than 30 metres. Three pinnacles belong with them: Hin Bida, roughly 8 kilometres from Ko Phi Phi Le, and Hin Mu Sang and Hin Jom, roughly 15 kilometres from Ko Phi Phi Don.

The reef follows the same logic. The same study records well developed fringing coral on the eastern sides of the islands and in places sheltered from southwest storms, growing down to about 8 to 10 metres at most sites and to about 15 to 20 metres at Ko Phi Phi Le. Massive Porites lutea, branching Acropora and the tabular Acropora hyacinthus dominate it, and gorgonian fans are common around Ko Phi Phi Don.

So depth at Phi Phi does not come from the reef. It comes from the limestone: the walls of Bida Nok and Bida Nai, the pinnacles further out, the sand between the rocks. A diver who wants 25 metres finds it beside a cliff, not on a slope. Published visibility in the same survey ran from 5 to 25 metres, which is a wide band and a fair warning.

The whole archipelago sits inside Hat Noppharat Thara – Mu Ko Phi Phi National Park, gazetted in the Royal Gazette of 6 October 1983 and now covering 242,437.17 rai, which the Department of National Parks converts to 387.90 square kilometres. The park has two halves, mainland beaches near Ao Nang and the islands, and they are priced differently.

The islands cost 400 baht, and the fee regulation says 200

Two Thai instruments set a price for this park and they do not agree. The first is the department regulation published on 9 December 2021 and in force from 7 June 2022, which sorted every national park in Thailand into four bands. Hat Noppharat Thara – Mu Ko Phi Phi sits in band two: 40 baht for a Thai adult, 20 for a Thai child, 200 for a foreign adult and 100 for a foreign child.

The second is older and is the one you actually pay. A department announcement dated 22 November 2007 fixes the rate for entering the Mu Ko Phi Phi part of the park, every island in it, naming Ko Phi Phi Le, Ko Mai Phai, Ko Yung, Ko Bida and Ko Poda. Thai adults 40 baht and children 20; foreign adults 400 baht and children 200. That rate has run unchanged since 2007.

It survived a serious attempt to cut it. In February 2017 some 500 Krabi tour and boat operators asked for the foreign rate to be halved to 200 and 100. The park advisory committee kept 400 and 200 and attached conditions: transparent collection, quality controls on tourism, and a grip on boat numbers, which had grown from about 500 vessels to about 2,000.

The money is not small. In the 2025 Thai financial year, October 2024 to September 2025, this park collected 648,920,480 baht, more than any other national park in the country, out of a national total of 2,208,128,028.86 baht. Second place, Mu Ko Similan, took 197,258,000. Budget the fee per park per day rather than per trip, and read the ticket: it is issued for the island area, not for the mainland beaches.

Maya Bay closed on 1 June 2018 and reopened without water access

The bay on Ko Phi Phi Le that a film made famous was shut by the Department of National Parks on 1 June 2018. It stayed shut for more than three years. It reopened on 1 January 2022, and the reopening is better understood as a new set of rules than as a return to normal.

Capacity is capped at 375 visitors per one hour round, from 07:00 to 18:00, which the department described as 11 rounds a day. Entry to the water is not allowed, a rule the department justified by visitor safety and by damage to coral. So Maya Bay is a beach you stand on, briefly, in a numbered slot.

Boats no longer enter the bay at all. The park built a floating pier and a raised walkway in Loh Samah Bay, on the opposite side of the island, along with mooring buoys and marker floats, plus toilets, a cooking building, benches and a viewing deck. Visitors arrive at the back and walk through.

Booking runs through the QueQ app and nothing else, opened on 20 December 2021 for arrivals from 1 January 2022, with reservations possible up to 60 days ahead. The same scheme broke this park into 42 separately bookable sites. None of that is a dive, but it shapes the boat traffic: the tour fleet is funnelled into Loh Samah on timed rounds, which is exactly where several Phi Phi Le dive sites sit.

The blacktip count at Maya Bay went from 161 to 278

The closure produced a measurable animal. During the years the bay was shut, the department recorded blacktip reef sharks, adults and juveniles, living in front of Maya Bay, and put the number at about 161.

The 2026 figure is larger and better documented. In September 2026, during the annual closure, the Marine National Park Study and Research Centre 3 in Trang surveyed the bay with the park and recorded a peak of 278 adult blacktip reef sharks close to the beach at first light on 2 September 2026, the highest reading in that financial year.

Fifteen drone flights gave an early morning mean of 251.67 ± 22.91 sharks and an evening mean of 57.25 ± 15.42. Most animals were adults over a metre, with three to five juveniles under a metre in the shallows. Twenty three baited video deployments recorded up to four juveniles in one frame, and twenty two water readings gave a mean temperature of 30.25°C and a mean salinity of 33.10 parts per thousand.

Counting sightings is not the same as counting animals. Photo identification, which works on individual fin markings, ran 333 blacktips through a Phi Phi catalogue between 1993 and 2019, and identified 62 individuals in Maya Bay alone between November 2022 and April 2023: 36 mature and 26 immature. Video and drone work from 2018 to 2024 found newborns of 30 to 60 centimetres and adults using the area all year, and a shark was seen giving birth in the bay in December 2019.

That is why the bay is treated as a nursery, and it is also the bay where nobody may enter the water. Divers meet blacktips elsewhere around the islands, in ones and twos, not in a column of 278.

Leopard sharks rest on the sand at Bida and lay eggs at Ko Yung

In 2024 the IUCN Shark Specialist Group named the Phi Phi Islands an Important Shark and Ray Area, 481.77 square kilometres of water from the surface to 35 metres. Two species qualified it. One is the blacktip. The other is the Indo-Pacific leopard shark, Stegostoma tigrinum, which the Red List classes as Endangered.

Phi Phi qualified as a resting area for it, and the reason is the behaviour. Unless divers disturb them, these animals are lying on the sand in more than 90 per cent of recorded observations. Between 2008 and 2010 it was common to see two or three resting close together at Bida Nok, Bida Nai, Hin Bida and Shark Point, and groups of up to five have been logged.

The scale of that is easier to grasp against the rest of the country. A dive log study covering 9,524 dives at 153 sites across Thailand between 2012 and 2016 found sightings of two or more leopard sharks at 15 sites. Eleven of those 15 sit inside the Phi Phi area.

The eggs are the other half. Divers have photographed leopard shark egg cases here since 1990, at 10 to 15 metres and often around gorgonians, with two main laying locations, Ko Yung and Ko Phi Phi Don. Laying starts with the northeast monsoon in October and November, and near term embryos are seen until April or May.

The trend under those numbers is downward. Earlier years produced up to 100 egg cases on a single dive; recent years are closer to ten. Thailand added the species to its schedule of protected wild animals in a ministerial regulation published in the Royal Gazette on 24 September 2024, where it is listed under its older name, Stegostoma fasciatum.

Maya Bay, Loh Samah and Lo Ko close from 1 August to 30 September

Every year the park shuts three bays on Ko Phi Phi Le: Maya Bay, Loh Samah and Lo Ko, from 1 August to 30 September. The department gives two reasons and both are literal. One is recovery, on land and underwater. The other is safety, because that window falls in the southwest monsoon and the sea runs rough.

The rest of the park stays open and keeps working through it. That is the distinction worth carrying, because a page saying the national park is open in August is true and useless: what closes is the named bay, and what stops a dive day is the state of the sea.

The park describes its own climate in terms that surprise people who have read the usual Thailand shorthand. Its rainy season runs from early May to December and its hot season from early January to April. That is eight wet months and four dry ones, not the six and six that brochures imply.

The traffic shows the shape of it better than a rainfall table. Krabi’s provincial administration counts every passenger through Pak Khlong Jilad, the port the Phi Phi ferries leave from, and logged 49,831 in January 2025 against 16,178 in September, the low point, out of 376,154 over the year.

The pattern inside that total matters more. All three Phi Phi operators carried passengers in every one of the twelve months, while the Ko Lanta operator at the same pier recorded none at all from May to October. Phi Phi thins in the wet season, it does not stop, and the crossing stays timetabled at two hours by ferry and one by speedboat. For choosing a mainland base, see Phuket versus Krabi.

The 2024 bleaching shut Phi Phi dive sites for ten months

In 2024 the Andaman bleached, and the park responded with closures rather than with advice. Announcements dated 13 May 2024 and 22 June 2024 suspended snorkelling and diving at a list of sites, starting on the Krabi mainland side of the park: Ko Kai, Ko Poda, Ko Daeng, Ao Railay and the deeper water at Ko Yawasam.

From 30 June 2024 the closure reached the islands themselves: Ao Loh Bakao, the north side of the Viking Cave, and the water in front of Ao Pileh. Park staff who dived those sites reported reef that had turned almost entirely white. The orders were made under sections 25 and 35(4) of the National Park Act B.E. 2562.

They were lifted on 17 April 2025, when the head of the park revoked the announcement of 22 June 2024 and reopened nine sites, having found recovery under way. The gap was close to ten months and it covered a full high season.

The lesson for anyone booking Phi Phi is procedural rather than ecological. Site closures here come from the park office, they are issued mid season, they name individual rocks and bays, and they are lifted the same way. The park next door runs on the same mechanism with its own calendar: Hin Daeng and Hin Muang have an annual closure of their own while Mu Ko Lanta around them stays open.

The King Cruiser wreck lies between Phuket and Phi Phi

The best known wreck in this corner of the Andaman is a ferry that sank on the way to Phi Phi. The King Cruiser went down on 4 May 1997 after striking a submerged rock near Hin Mu Sang, the pinnacle sold to divers as Shark Point. The Royal Thai Navy, which dived and surveyed the wreck on 5 April 2021, records that nobody was killed.

Where it lies is worth pinning down, because the marketing and the map disagree. Hin Mu Sang and its neighbour Hin Jom, known as Anemone Reef, sit about 15 kilometres from Ko Phi Phi Don, while operator accounts put the wreck somewhere between 25 and 32 kilometres from Phuket. Those distance figures come from dive businesses rather than from a chart and are triangulated rather than settled.

Depth is disputed in the same way. Published accounts put the seabed at 30 to 33 metres, and they agree on the direction of change: the shallowest point was once about 10 to 12 metres and is now nearer 16 to 18, because the superstructure has fallen in. The year of the major collapse is given as 2003 by some accounts and 2004 by others.

Hin Mu Sang itself carries real legal protection, and it is more recent than the dive literature suggests. A Department of Marine and Coastal Resources order, number 1148/2563, took effect on 23 September 2020 under section 17 of the Marine and Coastal Resources Management Promotion Act B.E. 2558. It bans traps and nets of every kind there, along with anchoring on reef and dumping waste, with a penalty of up to a year in prison, a fine of up to 100,000 baht, or both. The pinnacle it names in Krabi province is Hin Daeng.

What the 2004 tsunami did to the Phi Phi reefs, island by island

The waves reached western Thailand at about 09:55 on 26 December 2004, on a high spring tide. Run-up measured afterwards on Ko Phi Phi Don was 5.84 metres on the north coast, read from a trace on the wall of a house, and 4.58 metres on the south coast. The highest figure recorded anywhere in Thailand that day was 19.6 metres, at Ban Thung Dap.

Underwater the damage was smaller than the shoreline damage and much more local. A rapid assessment of 174 sites along the west coast found 105 unaffected or barely touched, 30 with 11 to 30 per cent of coral cover affected, 16 with 31 to 50 per cent, and 23 severely damaged with more than half the cover affected. That is 13 per cent severe against 60 per cent little or none.

The north took the worst of it: Ranong, Phang Nga and the Surin and Similan islands. The south came off lighter, with one exception the survey named, and the exception was Phi Phi. Around the islands the heaviest damage, up to 50 per cent, was at Ko Pai and Lolana Bay, with 30 to 50 per cent at the northern end of Ko Phi Phi Le.

Four sites came through almost untouched: Ko Yung, Laem Tong, Hin Phae and the southeast of Ko Phi Phi Le. Long term monitoring going back 15 to 25 years found coral cover reductions of 5 to 16 per cent at the worst four of 17 stations, and about 40 per cent at the southwest tip of Pai Island. Sedimentation killed coral at two sites around Phi Phi.

Recovery was measured rather than assumed. Settlement plates carried more than 17 coral spat per tile after four months, at damaged and undamaged sites alike, and recruit densities on natural substrate reached 7.2 per square metre per year three years on. The published estimate was full recovery in 5 to 10 years, provided nothing else went wrong. Bleaching went wrong.

Six dive businesses at Phi Phi, and three of them are filed under Krabi

The operator picture here is small and unusually uniform. Six dive businesses at Phi Phi appear in the SSI register of affiliated centres, read on 4 September 2026, and all six are SSI entries. None of them appears in the IKO or VDWS registers, and none is a Green Fins member. Five of the six publish a website in the register.

The addresses in that register look wrong until you check a map. It files three of the six under Krabi, one under Mueang Krabi, Krabi, and two under Koh Phi Phi. The islands are in Krabi province, so a register entry that says Krabi is recording an administrative fact rather than making a mistake.

What an entry settles is narrow. It says the body lists the business on the date given, and nothing about the teaching, the boats, the briefings, the kit or whether the centre is trading this season. Every entry on the Phi Phi operator list links back to the register page it was read from.

Thailand keeps no compulsory register or licence for a recreational dive centre that a reader could look up, which is why absence from a membership list proves nothing: which registers can be read logs what each source returned and on what date.

So the checkable part of a Phi Phi trip is the park, not the school. The fee, the closure dates, the bay rules and the site suspensions are all published, dated and enforceable. Plan around those, and treat what a brochure says about the diving itself as a claim rather than a fact.