top of page
  • Deep Andaman Team

When to Dive the Similan Islands to See Manta Rays

Updated: Jan 25, 2020

Diving with manta rays in Thailand is one of the top attractions for scuba divers when planning their holidays, and the Similan and Surin Islands marine parks are well known for being one of the top locations in the world to scuba dive with manta rays. So it stands to reason that when we receive inquiries from customers looking to book one of our Similan Island liveaboard trips or Myanmar liveaboard trips, that one of the most popular questions we are asked is which trip dates give the best probability of seeing manta rays.

The desire to go diving with manta rays is completely understandable, and even our trip leaders and regular divers admit that they could never tire of the feeling of elation as these majestic beauties sweep through the dive site and cruise over their heads as they explore the dive sites below. It’s just magical, and we feel incredibly lucky, as not every Thailand diving location is as fortunate to have such regular experiences diving with manta rays as we enjoy.

About Manta Rays

Unlike many ray species such as blue-spotted stingrays and Kuhls rays, which you’ll see in on the sea bed at the majority of Similans Islands dive sites and indeed other Thailand diving locations too, manta rays are pelagic. This means they are normally found swimming over larger areas, and very rarely spend much time on the ocean floor. Fun fact: Manta rays can only breathe when they are in motion, so they are perpetually on the move!

Manta rays are filter feeders and sustain themselves on zooplanktons such as juvenile fish, krill, crustaceans, and mollusks. Despite the relatively small size of their food, manta rays are large in comparative mass and tend to have a body span of 3-5 meters, although it is possible for them to grow as big as 6-7meters. They also have the largest brain to body size ratio of any fish, which scientists state is an excellent indicator of intelligence. Manta rays are identified using the pattern of spots on their underside. Just like a fingerprint, each manta ray has a unique pattern on its belly, meaning scientists can use these markings to identify and track manta ray activity based on sightings by scuba divers over time. It is estimated that the average lifespan of a manta ray can be 50 years plus.

What makes for a Good Manta Ray Season?

Manta rays are drawn to both an abundance of food, and the opportunity to visit cleaning stations. Cleaning stations are specific patches of reefs where pelagic fish go to have their bodies and mouths cleaned of dead skin and parasites by cleaner wrasses.

The Manta rays we see scuba diving the Similan islands are on their seasonal migration route based on their feeding habits. Hot weather and strong currents provide the perfect conditions to bring rich plankton up from the depths toward the surface, where the manta rays can easily scoop up their daily fill. This combined with the availability of cleaning stations makes Similan Island dive sites perfect for manta ray diving.

Manta Ray Season in the Similans

Historically, guests aboard the Deep Andaman Queen have seen manta rays on departure dates throughout our entire Andaman liveaboard season. However, the best time is from December to April, where they can be seen almost daily. Once they arrive, they generally stick around for a while, often for weeks and months at a time. It is possible for them to disappear sporadically though, and while typically this is just for a few days at a time, it can on some occasions be a couple of weeks. So like all Similan islands marine life sightings, there is an element of luck when it comes to being in the right place at the right time. If you join any one of our liveaboard trips during the manta ray season, you do have a good chance of seeing them though. In fact, we provide the best Thailand liveaboard options as our itineraries are scheduled over 5 days and include 14 dives, so your chances of a manta ray encounter are maximized. After all, the more time you spend underwater, the more you are likely to see! This is not simply true for manta ray diving, but for whale shark diving and other marine life sightings too.

The Best Similan Dive Sites for Manta Rays

According to current research and identifications based on reports and photographs from scuba divers, the resident Similan Island manta ray population is considered to comprise of around 20 members. Generally, the best dive sites for manta ray sightings are the big pinnacle sites, where currents can be stronger and therefore liable to transport plankton up from the depths. The two best dive sites for manta ray diving in the Similans are Koh Tachai and Koh Bon, most likely as these are home to some of the main cleaning stations in the Similans archipelago as well as serving as popular plankton feeding stations.

Manta Rays are not only seen on our Thailand liveaboard itineraries. Guests onboard one of our North Andaman trips that explore up into Myanmar have great chances of spotting a manta or few at Black Rock, which is where we spend a full day of diving on day 4 of the trip. Manta sightings are also possible at Fan Forest.

So…are you excited about seeing your first manta ray with us? We hope so! All you need to do is book in your holiday leave and contact us to secure your preferred date. As manta ray season and whale shark season are both very popular times, some itineraries do get fully booked, so make sure you plan your trip ahead of time to avoid disappointment. You can check both boat schedules and trip availability online, plus the homepage of our website features our most up to date liveaboard diving deals. You can book either online or via email by contacting one of our helpful and friendly service team at

See you onboard soon!

1,029 views0 comments


bottom of page