Diving around Krabi: what is down there, and when to go

Krabi suits a first dive or a beginner's course: the sites closest to Ao Nang are shallow, and the water is warm. If you are already certified and travelling for the diving, the sites dive operators rate most highly are further out, around Phi Phi and at Koh Haa, which is reached mostly from Koh Lanta, and the season runs from about November to April.

What follows covers the difference between a try dive and a course, the main areas from Ao Nang outwards, the season and the state of the coral, and the rules that have applied to every diver in Thailand since April 2025. We do not name dive centres, and the descriptions of sites come from dive operators: read them as what a site can hold on a good day.

Snorkelling or diving

Most island days from Krabi include a snorkelling stop, and for many visitors that is enough: a mask, the surface and the first two or three metres of reef. Diving takes you below that, with a tank, an instructor or a dive guide, and a boat that goes to the dive sites rather than the beach stops.

If you are not sure you want to breathe underwater, start with snorkelling on an island day, and keep the try dive for later in your stay.

Snorkelling around Krabi: what you will actually see

A first dive or a course

A try dive, sold under names such as Discover Scuba Diving, is a supervised experience, not a qualification. With PADI, it is open from the age of 10 and goes no deeper than 12 metres. Under the Thai rules in force since April 2025, an instructor may take no more than two people at a time on an introductory dive.

The Open Water course is the first certification, which lets you dive afterwards without an instructor, with a buddy, down to 18 metres. PADI says it takes two to four days; the minimum age is 15, or 10 for the junior version, which has stricter depth limits. Under the Thai rules, an instructor takes no more than four students at a time.

Before either, you fill in a medical questionnaire. Some answers, about the heart, the lungs or your fitness among others, mean you need a doctor's approval before you dive, and the form says not to dive if you are pregnant. If you have a condition you are unsure about, see your doctor before you travel rather than hoping to find one on holiday. Ask the centre too what swimming test the course includes.

Near Ao Nang

The sites closest to Ao Nang, around Koh Poda, Koh Tup, Chicken Island and the bays of Ao Nang and Railay, are the shallow ones, which operators describe as suited to beginners and to try dives. They list hard and soft corals, reef fish, blue-spotted stingrays and turtles seen at times off Koh Poda.

Treat these as training sites rather than a reason to travel. They are near the surface, which is where the 2024 bleaching hit hardest, and the west side of Chicken Island has stayed closed to protect its reef.

Phi Phi

The Phi Phi islands are the main day-diving area from Krabi, reached by dive boats from Ao Nang and from Phi Phi Don itself. The sites operators rate most highly are Bida Nok and Bida Nai, two islets south of Phi Phi Leh, where leopard sharks are often seen resting on the sand and hawksbill turtles at times. PADI describes the two as suiting beginners as well as more advanced divers.

The sites are in the Hat Noppharat Thara-Mu Ko Phi Phi national park. The park fee for Phi Phi Don, Phi Phi Leh and Bamboo Island is 400 baht per foreign adult, as of October 2026, and one dive operator reports an extra daily charge for divers. Ask whether your price includes them.

Shark Point, Anemone Reef and the King Cruiser

Between Phuket and Phi Phi, three sites lie close together: Shark Point, a group of pinnacles with soft corals; Anemone Reef, a submerged pinnacle covered in anemones; and the wreck of the King Cruiser. They are dived mostly from Phuket, and operators sell them as day trips from Krabi too.

The King Cruiser was a car ferry. On 4 May 1997, on its way from Phuket to Phi Phi, it struck Anemone Reef and sank; all 561 people aboard were rescued. It now sits upright on sand, with its bottom at about 30 metres, and its upper decks have collapsed. It is a dive for certified divers, not for a try dive, and the depth puts the lower parts beyond the 18 metres of a first certification.

Do not confuse this Shark Point with Phi Phi Shark Point, another site south-east of Phi Phi Leh: check which one your boat is going to.

Koh Haa, and further out

Koh Haa, a group of small islands in the Mu Ko Lanta national park, is where operators place some of the best diving in the area: a sheltered sandy lagoon that suits beginners, caverns for divers with the training, and a deep channel for experienced divers. Operators say whale sharks pass occasionally, mostly from February to April; do not book a trip on it. Koh Haa is reached mostly by day boat from Koh Lanta, in the season, or on a liveaboard.

Check that it is open. In the national parks department's 2026 schedule, Koh Haa is closed from 1 August to 30 September. In 2026 it was also closed from 11 June because of Portuguese man o' war, and we have found no announcement of its reopening.

Further out still, the pinnacles of Hin Daeng and Hin Muang are reached mostly on liveaboards, and close from 1 August to 30 September too.

Koh Lanta: the day trips to Koh Rok and Koh Haa

When to go, and the coral

Dive operators agree on the outline: the season runs from about November to April, with the calmest and clearest water from about January to March near Krabi, and into April at Phi Phi. From May to October, the southwest monsoon brings swell and plankton that cloud the water, and the boats to the more distant sites run less or not at all. The water is warm all year, about 27 to 31 °C according to operators.

The coral has had two bad years. In April 2024, unusually warm water set off bleaching along the Andaman coast, and the Phi Phi national park closed several of its dive and snorkelling sites on 13 May 2024; it reopened ten of them on 17 April 2025. In late April 2026, park officials measured the water at 32 °C near Ao Nang and found a fifth of the living coral turning pale. We have found no newer survey: expect healthy patches next to pale or dead ones, and a picture that changes from year to year.

The rules, and your flight home

Since 22 April 2025, national rules have applied to every dive in Thai waters, for five years. Every trip must have a certified dive supervisor or assistant, who briefs you before the dive.

Touch nothing. No contact with coral or any sea creature, no feeding fish, and stay at least two metres above coral heads. Kicking up sediment through poor fin control is banned too.

Leave the camera unless you qualify. A camera is allowed on a dive only if you hold an Advanced Open Water certification or equivalent, or have logged at least 40 dives, and you may be asked for proof. On a try dive or a first course, it stays on the boat.

Check your sunscreen. Sunscreens containing oxybenzone, octinoxate, 4-MBC or butylparaben have been banned in Thailand's marine national parks since August 2021.

Leave time before your flight. Divers Alert Network recommends at least 12 hours between a single no-decompression dive and a flight, and at least 18 hours after several dives in a day or several days of diving. Plan your last dive for the day before you fly, not the morning.

Not for you if you cannot travel between November and April and diving is the reason for the trip, if you are hoping for big animals on a schedule, or if you would rather keep your feet on a boat: a snorkelling day shows you the reef top without a course.

Read nextSnorkelling around Krabi: what you will actually see ▸

Read nextPhi Phi from Krabi: a day trip or a night on the island ▸