The clearest water and best snorkelling in the Gulf — turtles, reef sharks and the Koh Nang Yuan sandbar. Here's the crossing, itinerary, fees and how to do it in a day. Updated July 2026.
Koh Tao sits about 85 km north of Koh Samui across open water — a genuine 1.5-hour speedboat run each way, and the stretch between Koh Phangan and Koh Tao can be considerably rougher than the sheltered waters around Ang Thong. Seasickness is a real consideration for this specific trip.
The reward is water quality. Koh Tao is the region's premier snorkelling destination — visibility often 15–30 m versus the 5–15 m typical at Ang Thong — with reliable turtles and reef sharks. If snorkelling is your priority, this is the trip. If you want scenery and a calmer day, Ang Thong wins.
Shark Bay is the most reliable place in the region to see green sea turtles daily and harmless juvenile blacktip reef sharks in shallow water — combined with the postcard Koh Nang Yuan sandbar and viewpoint.
North of Koh Samui
Typical visibility
A guided speedboat tour with hotel pickup is the practical way to do Koh Tao in a day.
| Option | Crossing time | Notes |
|---|---|---|
| Tour speedboat | ~1.5 hrs each way | What most snorkelling day tours use; departs north-coast piers |
| Lomprayah catamaran | ~1.5–3+ hrs | More stable, has toilets & cabin; stops at Koh Phangan en route |
| Songserm ferry | ~3–4 hrs | Slower and cheaper, from Nathon Pier |
Tours leave from north-coast piers — Bophut/Bangrak and Maenam — or Nathon on the west coast. Morning departures (first Lomprayah boats around 08:00) are essential and the seas are calmest early. On arrival at Mae Haad Pier, everyone pays a 20 THB municipal island tax that funds local marine conservation.
About 8–9 hours door-to-door for many operators, visiting 2–5 snorkel spots depending on conditions.
Air-conditioned minivan to the north-coast pier, light breakfast, board the speedboat.
Roughly 1.5 hours across open water, passing Koh Phangan.
One or two Koh Tao bays — the crew picks the best for the day's conditions (Mango Bay, Hin Wong, Shark Bay or Aow Leuk).
Thai buffet or restaurant lunch, then transfer to Koh Nang Yuan.
Beach time, snorkelling at the Japanese Gardens, and the 10–15 minute climb to the famous viewpoint before the ~90-minute ride home.
Never try to swim between Koh Tao and Koh Nang Yuan — the channel has strong currents. Stick to the marked snorkel areas and follow the crew.
The best living coral is along rocky bay sides and sheltered sites — not the boat-parking shallows.
The signature stop for juvenile blacktip reef sharks and the region's most reliable daily turtle sightings. Best early morning and late afternoon.
A crescent bay with clear, shallow water — one of the most reliable spots for baby blacktips and turtles. Beginner-friendly.
Some of Koh Tao's best-preserved coral and big fish schools. Sheltered, quieter, and best in calm morning conditions.
On Koh Nang Yuan's east side — the best coral snorkelling in the area, dense and shallow. Go early before the day-trip crowds.
Many shallow areas have dead-coral patches from bleaching and heavy visitor pressure. This is very good regional snorkelling — not pristine, world-class reef. Ask your operator to include Shark Bay for the marine life.
Koh Nang Yuan is privately operated, so day-trippers pay an entrance fee on arrival — usually not included in the tour price. Bring cash.
| Item | Typical price |
|---|---|
| Shared speedboat day trip (adult) | ~2,900–5,000 THB |
| Private speedboat charter | ~30,000–46,000+ THB / boat |
| Koh Nang Yuan entry (foreign adult) | 250 THB |
| Koh Nang Yuan entry (child 2–12) | 120 THB |
| Koh Tao pier / island tax | 20 THB |
Single-use plastic bottles and cans are banned at Koh Nang Yuan and confiscated on arrival. Bring a refillable bottle — and small bills for the entrance fee.
Older pages still quote 100 or 200 THB, but the most recent local sources point to 250 THB per foreign adult. Confirm the current fee and whether it's included when you book.
Three well-reviewed Koh Tao & Koh Nang Yuan snorkelling day trips departing directly from Koh Samui. Prices and dates update in real time.
The most-reviewed Koh Tao day trip from Samui: a full day of snorkelling around Koh Tao's best bays plus the Koh Nang Yuan viewpoint and sandbar, with lunch and hotel transfers included. A dependable first choice.
The straightforward speedboat run to Koh Tao and Koh Nang Yuan — the fastest way across and the format most day-trippers book, with snorkel stops chosen for the day's conditions.
A capped-size trip for a more relaxed day with fewer people on the boat and at each bay — worth the premium if you'd rather skip the big-group crush at Koh Nang Yuan.
Morning departures are calmest. Aim for the dry, settled window.
Calm seas, hot sun and peak visibility (often 20–30 m). The safest bet for a comfortable crossing and clear water.
Shoulder conditions; east-coast bays often stay calm, and a settled September–October spell can deliver the year's best clarity.
Northeast monsoon and Koh Tao's rainy season — rougher seas and more cancellations. November is the least reliable month.
If the forecast is windy or you're very motion-sensitive, the sheltered Ang Thong day trip is the calmer-sea alternative — dramatic scenery, a lagoon and kayaking, on a gentler crossing.
A stable big-boat cruise to Ang Thong is the most comfortable substitute when the Koh Tao crossing looks rough. It's the most-reviewed Ang Thong trip and leaves daily from Koh Samui — live availability below.
Marine parks now enforce a ban on chemical sunscreens (oxybenzone, octinoxate, 4-MBC, butylparaben) with fines up to 100,000 THB. Koh Tao isn't a national park, but the reef-safe expectation is now standard across the region's boat tours, and bag checks can occur — bring mineral sunscreen or cover up.
Koh Samui is a springboard for the whole Gulf of Thailand.
Beyond the Koh Tao and Koh Nang Yuan snorkelling day trip, from Koh Samui you can explore the limestone islands and Emerald Lagoon of Ang Thong Marine Park, take the easy family trip to Koh Tan and Koh Madsum (Pig Island), or book a private speedboat charter, a sea-kayaking adventure or a sunset cruise. Chase turtles at Shark Bay or the viewpoint hikes across the archipelago — live options are below.
Compare Koh Tao snorkelling trips and the calmer Ang Thong alternatives — inclusions, prices, ratings and free cancellation.