The Andaman Sea is home to a remarkable range of marine megafauna that most Phuket visitors never encounter because it is not marketed prominently and the encounters require going further from shore than a standard day trip reaches. But they are there. Here is what exists and how realistically you might see it.
The world’s largest fish — docile plankton-feeders that can reach 12 metres in length — are present in the Andaman Sea seasonally, primarily from December to April. The highest-probability encounter site is Richelieu Rock near the Surin Islands, 180 kilometres north of Phuket, which is accessible by liveaboard. Day trips from Phuket reach the rock only in good conditions and with long travel time each way.
Whale shark encounters are not guaranteed at any site. The animals follow plankton concentrations and their movements are not predictable on a day-by-day basis. Operators who claim guaranteed encounters are selling something they cannot deliver. What Richelieu Rock offers is the highest probability in the region — encounters occur multiple times per week during the season on many liveaboard trips, but not on every trip.
Bryde’s whales — medium-sized baleen whales reaching 12 to 15 metres — are occasionally sighted in the deeper water of the Andaman Sea between Phuket and the Similan Islands. These sightings are rare and opportunistic rather than the result of targeted whale-watching trips. If you are on a boat that travels the open Andaman Sea routes, keeping an eye on the horizon is always worthwhile.
These short-beaked, rounded dolphins inhabit the shallower areas of Phang Nga Bay and are one of the lesser-known wildlife encounters available on our Phang Nga Bay day trips. We know the areas of the bay where they are most commonly seen and we take routes that give us the best chance of an encounter. Sightings are not guaranteed but are not rare either — they occur on perhaps one in three trips through the right areas. When they do appear, the encounter is genuinely moving: small groups surfacing close to the boat, curious rather than evasive.
More reliably encountered than any other cetacean in the region, spinner dolphins are often seen in the open water between Phuket and the Phi Phi Islands. They frequently approach speedboats and ride the bow wave — one of the more joyful spontaneous wildlife encounters available from any boat trip in the region. There is no way to plan for it specifically; it simply happens on some crossings and not on others.
Any wildlife encounter at sea should be approached with the animals’ wellbeing as the primary consideration. Do not position the boat between animals and their direction of travel, do not approach nursing or resting animals, and do not enter the water with whale sharks unless this is explicitly sanctioned by the national park authority at the relevant site. The encounters that are genuinely extraordinary are almost always the ones where the animal came to you rather than the other way around.
➤ Phang Nga Bay trips give the best chance of Irrawaddy dolphin encounters
— Captain Mark
Exceptional, uncrowded island day trips from Phuket. Family-owned and operated since 2004.
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