Similan Islands – Underwater Wonderland: The Coral Kingdoms of the Andaman Sea

The first time I saw the Similan Islands, I was honestly speechless. And that’s saying something because my friends know I’m rarely at a loss for words! The boat was approaching Island #4 (Donald Duck Bay, named for a rock formation that supposedly resembles the cartoon character—though I still can’t really see the resemblance), and the water gradually shifted from deep blue to this impossible turquoise that seemed to glow from within.

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I’m not typically a “beach person” (I burn like a lobster and sand gets EVERYWHERE), but there was something about these islands that changed something in me. Maybe it was the perfect isolation—no cell service forcing me to actually disconnect—or perhaps it was the first turtle I spotted while snorkeling near the shore, moving with such grace it made me feel clumsy by comparison.

The Similan Islands are a protected marine national park in Thailand’s Andaman Sea, about 84 kilometers northwest of Phuket. They’re actually a small archipelago of nine islands (similan means “nine” in the local Yawi language), each with those postcard-perfect white sand beaches, massive smooth granite boulders, and the kind of underwater visibility that makes divers weak at the knees.

I’d been dreaming about visiting ever since I saw a documentary about the Andaman Sea years ago. The footage of coral gardens and manta rays had me convinced I needed to see it with my own eyes. But honestly? Nothing prepared me for how it actually felt to be there, floating above vibrant coral formations with fish darting around me like I was just another curious visitor to their world.

The Journey: Boats, Bumps, and a Bit of Seasickness

Getting to paradise, as it turns out, requires some effort—which is probably why the Similan Islands haven’t been completely overrun by tourism (yet). Most visitors depart from either Phuket or Khao Lak, with the latter being closer and therefore the more popular jumping-off point.

I started my journey from Phuket, mainly because I found a good deal on accommodations there and wanted to explore the island for a few days before heading to the Similans. In retrospect, I probably should have just gone straight to Khao Lak to save travel time, but hey—live and learn.

There are basically two ways to experience the Similans: day trips or liveaboards (boats where you actually sleep on board for multiple days). I initially wanted to do a liveaboard since everyone raves about how you get access to the best dive sites early in the morning before day-trippers arrive, but my budget and schedule didn’t allow for it. So day trip it was!

I booked through what seemed like a reputable tour company online about a week before my trip. It cost around 3,800 baht (roughly $110), which included transportation from my hotel, the national park entrance fee, lunch, snorkeling equipment, and an English-speaking guide. Not cheap, but not outrageous either. Wait—I just double-checked my notes, and it was actually 4,300 baht. Memory’s a funny thing.

The morning of the trip, I was picked up at the ungodly hour of 6:00 AM (I am NOT a morning person) and driven to the pier at Tablamu in Khao Lak, about a 2-hour drive from Phuket. I dozed off during most of the ride, waking occasionally to catch glimpses of rural Thailand passing by my window.

At the pier, chaos reigned as dozens of tour groups attempted to find their respective boats. I’m embarrassed to admit I initially followed the wrong group and almost boarded the wrong speedboat before a guide called me back. In my defense, it was early, and I hadn’t had enough coffee!

The boat ride itself was… an experience. I’d read that the journey takes about 1.5 hours by speedboat, which sounded manageable. What I didn’t account for was the choppiness of the sea that day. About 30 minutes in, I started feeling queasy. By the 45-minute mark, I was hanging over the side of the boat, making friends with the fishes in the most unfortunate way possible.

Pro tip: Even if you don’t normally get seasick, take dramamine or another motion sickness medication BEFORE boarding. The Andaman Sea can be unpredictable, and those speedboats bounce. A lot.

The silver lining? I wasn’t alone in my misery. About a third of our boat was in the same condition, including a tough-looking guy who had earlier bragged about his extensive sailing experience. The sea is the great equalizer, I suppose.

Just when I thought I couldn’t take anymore, the islands appeared on the horizon, and the waters began to calm as we entered the protected area between the islands. The nausea subsided almost immediately, replaced by mounting excitement as we approached our first stop.

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One thing to note: The Similan Islands are closed annually from May 15 to October 15 for monsoon season and coral restoration. I nearly made the mistake of planning my trip for early May, not realizing how close I was cutting it to closure time. Always check the current park status before booking anything!

Underwater Magic: Diving into Another World

First Plunge: Nerves and Wonder

Despite the rocky start to the day (pun intended), everything changed the moment I put on my mask and fins and slipped into the water at our first snorkeling spot near Island #4.

I should mention I’m not a certified diver—something I regret and plan to remedy soon. But even snorkeling in the Similans offers an incredible window into this underwater kingdom. The water was so clear it felt like flying rather than swimming, with visibility extending at least 30 meters.

My first “wow” moment came about five minutes in, when I floated above a brain coral the size of a small car. It was a perfect dome, with its characteristic maze-like pattern clearly visible. Around it, damselfish darted in and out, electric blue against the coral’s tan surface.

I remember thinking, “This can’t be real,” but it was. And it only got better.

At one point, I found myself in the middle of a school of yellowtail fusiliers—hundreds of them moving in perfect synchronicity, parting around me like I was just another obstacle in their path. I spun slowly, surrounded by this living tornado of yellow and blue, completely disoriented in the best possible way.

Then there was the turtle. I’d been in the water maybe 20 minutes when our guide made the underwater signal for “turtle” and pointed ahead. I kicked harder (probably too hard, in my excitement) and there it was—a green sea turtle effortlessly gliding through the water, munching on some sea grass. I followed at a respectful distance, watching this ancient creature go about its day, completely unbothered by my presence. I swear I almost cried into my mask.

What Makes This Place Special

The Similans are often ranked among the top ten dive sites in the world, and after experiencing even a fraction of what they offer, I understand why. The biodiversity here is staggering—over 500 species of hard and soft corals, 650 species of fish, and larger marine creatures like whale sharks, manta rays, and several turtle species.

What makes this ecosystem unique is the convergence of two distinct underwater landscapes. On the eastern side of the islands, you find gently sloping coral gardens—expansive fields of colorful coral punctuated by sandy patches. The western side, facing the open Andaman Sea, features dramatic underwater granite boulders creating swim-throughs, caves, and channels that larger pelagic species love to visit.

I was lucky enough to visit both types of sites. At a spot called East of Eden (near Island #7), I floated above a garden of staghorn and table corals stretching as far as I could see. Anemones waved their tentacles in the gentle current, each hosting a family of clownfish that darted in and out with surprising aggression whenever I got too close. Note to self: Nemo is way more territorial than the movie suggests.

Later, we moved to a site near Island #9 with massive underwater boulders. Swimming through the channels between these giants was both thrilling and slightly intimidating—the scale makes you acutely aware of how small you are. At one point, I spotted a leopard shark resting on a sandy patch between rocks. My heart nearly stopped until our guide signaled that they’re completely harmless to humans. Still, the primal fear of seeing a shark in the wild is something I won’t forget.

The diversity of marine life I saw in just one day was mind-boggling: parrotfish using their beak-like mouths to scrape algae from coral, moray eels peering out from rocky crevices, giant trevallies hunting smaller fish, and tiny nudibranchs (sea slugs) in psychedelic colors crawling across the reef.

I keep thinking about how places like this might not exist for future generations. Our guide mentioned that the 2010 coral bleaching event damaged about 80% of the shallow coral in the Similans, though much has recovered since then. The Thai government’s decision to close the islands for half the year is helping, but global warming threatens reefs worldwide. I wonder if my hypothetical grandkids will ever see what I saw that day.

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Beyond the Blue: Island Exploration and Beach Time

After several hours in the water (I lost track of time completely), we headed to Island #8, also known as Koh Similan, for lunch and beach time. This is the largest island in the group and one of the few where visitors are allowed to go ashore.

Stepping onto that white sand beach felt surreal after the underwater adventure. The sand was so fine it squeaked under my feet, and the contrast between the turquoise water, white beach, and green jungle interior was almost too perfect—like someone had cranked up the saturation on reality.

Lunch was a surprisingly good buffet of Thai dishes set up under a canopy: fried rice, massaman curry, stir-fried vegetables, and fresh fruit. I piled my plate high, suddenly aware of how hungry I was after all that swimming. I sat on a fallen log, sand between my toes, watching monitor lizards slinking along the edge of the beach. They’re enormous—up to two meters long—but apparently harmless unless provoked.

After eating, I had about an hour to explore before we needed to head back to the boat. A short trail leads from the beach up to a famous rock formation called “Sail Rock” or “Donald Duck Rock” (depending on who you ask). It’s a fairly easy 15-minute hike, though the humidity in the jungle had me drenched in sweat almost immediately.

The view from the top was worth every sweaty step—a panorama of the Andaman Sea stretching to the horizon, with the curved white beaches of the island below. I’m not usually one for just sitting and staring at views (I get antsy), but I found myself perched on that rock for a good twenty minutes, just… being. No photos (though I took plenty), no checking the time, just watching the boats move across that impossible blue water.

One thing to note about the Similans: there are virtually no facilities beyond basic toilets and the ranger stations. No shops, no cafes, no convenience stores—just nature. It’s refreshing but requires planning. I ran out of water during my hike and was parched by the time I got back to the beach. Rookie mistake.

Practical Tips from a Slightly Sunburned Traveler

Diving and Snorkeling Preparation

If you’re a certified diver, you’ve got a leg up on me. The Similans offer some of the best diving in Thailand, with sites suitable for all experience levels. Popular dive spots include Elephant Head Rock (named for its shape), East of Eden, and Breakfast Bend.

For newbies like me, consider getting Open Water certified in Phuket or Khao Lak before your trip. Courses run around 10,000-15,000 baht ($300-450) and take 3-4 days. In retrospect, I really wish I’d done this—while snorkeling was amazing, divers get to see so much more.

If you’re sticking with snorkeling, bring your own mask if possible. The rental equipment was decent, but having a mask that fits perfectly makes a huge difference in enjoyment. I bought a basic set in Phuket for about 800 baht ($25) and was glad I did.

Oh, and underwater cameras! This is my biggest regret. I thought my ancient GoPro would be fine, but it died halfway through the first snorkel session. Several people on our boat had newer models or those phone pouches that let you take underwater shots. I was so jealous watching them capture perfect turtle moments while I just had to commit everything to memory.

For liveaboard trips, book well in advance (like, months) during high season (November-April). The best boats fill up quickly, especially around Christmas and New Year. Prices range widely from budget (around 15,000 baht for 2 days) to luxury (50,000+ baht for 4 days).

Being an Eco-Conscious Visitor

The Similans’ protected status exists for a reason. The ecosystems here are incredibly fragile, and irresponsible tourism is a genuine threat. Our guide was strict about not touching coral (which can kill it), not feeding fish (which disrupts natural behaviors), and not taking anything—not even shells—from the islands.

I witnessed a couple from another boat standing on coral to take a selfie. Our guide actually swam over to speak with them, which was both awkward and necessary. It’s easy to forget that coral is a living organism, not just an underwater rock.

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Most tour operators claim to be “eco-friendly,” but actions speak louder than words. Look for companies that:
– Limit group sizes
– Use mooring buoys rather than anchors
– Provide environmental briefings
– Actively participate in conservation efforts

I researched several operators before booking and chose one that donates a portion of proceeds to coral restoration projects. Did I pay a bit more? Yes. Was it worth it? Absolutely.

I’m not sure if my small choices make much difference in the grand scheme of things, but I tried. The oceans are in trouble, and places like the Similans show us exactly what we stand to lose.

Practical Matters

A few random tips that might save you some headaches:

• The national park fee (currently 500 baht for foreign adults) is sometimes included in tour prices, sometimes not. Double-check to avoid surprises.
• Bring more water than you think you’ll need. The combination of sun, salt water, and swimming dehydrates you quickly.
• Wear a rash guard or T-shirt while snorkeling. I thought my back was well-sunscreened… narrator: it was not. Three days of painful sunburn followed.
• Seasickness pills! I cannot stress this enough. Take them 30-60 minutes before departure.
• There’s no cell service on the islands. Download maps, e-books, or music before you go if you’ll want them during downtime.
• Bring cash. Credit cards aren’t accepted for anything on the islands (though there’s not much to buy anyway).
• The best visibility is typically from December to April. I went in late January and conditions were perfect.

The Verdict: Worth Every Baht, Bump, and Sunburn

So was the journey to the Similans worth it? Despite the seasickness, sunburn, and considerable expense?

Without hesitation, yes.

There are travel experiences that are enjoyable, those that are memorable, and then there are those rare few that fundamentally shift something in your perspective. The Similans fall into that last category for me.

I’ve snorkeled in several places around the world, but nothing compared to the vibrant underwater tapestry of the Similans. The combination of exceptional visibility, healthy coral, abundant marine life, and protected status creates something truly special.

The experience wasn’t perfect. The boats were crowded (though less so than at more accessible sites like Phi Phi), the journey was rough, and a day trip only scratches the surface of what the islands offer. If I could do it again, I’d definitely splurge on a liveaboard to have more time and access to the more remote sites.

I’m also conflicted about tourism in such fragile ecosystems. Even with regulations and park closures, thousands of visitors impact these islands each year. I was part of that impact. Yet without tourism revenue, would there be resources to protect these areas at all? It’s a complicated balance.

What stays with me most isn’t just the visual beauty, but a moment of perfect peace. I was floating above a coral garden, the sun creating light beams through the water, when a school of barracuda passed in the distance, their silvery bodies catching the light. In that moment, I felt completely present and connected to something much larger than myself.

That feeling—more than any photograph or story—is what I carried home from the Similan Islands. And it’s why, despite the costs and complications, I’m already planning my return trip—next time as a certified diver, ready to explore even deeper into these underwater kingdoms.

Was it the best trip of my life? I’m still deciding, but it’s definitely in the running. Some places claim to be paradise and disappoint. The Similans quietly exceed expectations, revealing their treasures to those willing to make the journey.

This article reflects my personal experience visiting the Similan Islands in January 2023. Park regulations, prices, and conditions may have changed since then.