Koh Tao Diving Guide: Open Water THB 9,900 to 12,000
A PADI Open Water course on Koh Tao costs THB 9,900 at Isla Tortuga Divers and THB 12,000 at Siam Scuba. You can start at age 10 and dive to 18 m once certified. February to May has the best visibility. The chamber phone is +66 81 081 9777.
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Learn to dive on Koh Tao
Koh Tao is where many people take their first dive. Anyone aged 10 or older can learn with PADI. Children aged 8 or older can try scuba in a pool.
The Open Water course ends with four open water dives, usually over two days, after the pool skills. You can finish in as little as 2 to 4 days. Once certified you dive anywhere in the world up to 18 m.
Junior divers become full Open Water Divers at age 15.
What a course costs
Prices differ by school, so compare what the total includes.
| Course | Isla Tortuga Divers | Siam Scuba |
|---|---|---|
| Open Water | THB 9,900, 3 full days | THB 12,000 |
| Advanced Open Water | THB 9,000, 2 days | THB 11,000, 1.5 days |
| Discover Scuba, 1 dive | THB 2,500 | THB 2,600 |
Scuba Shack runs the Open Water over four days at THB 12,000, with materials, equipment, certification and the online manual included. Dives 3 and 4 go to a maximum of 18 m.
Plan your dive week
Book the Open Water first, then decide how far to go. If you only want a taste, the one-day Discover Scuba dive is THB 2,500 at Isla Tortuga Divers. Keep your first dives at Twins, where the depth runs from 5 to 19 m and the rating is Easy.
After certification, Advanced Open Water is a 2 day course at THB 9,000 at Isla Tortuga Divers. Siam Scuba runs it as 1.5 days and 5 adventure dives for THB 11,000. Sail Rock and Chumphon Pinnacle are both rated Advanced, so they suit the end of the week, not the start.
Pick the months with care. Choppy seas hit the north-shore sites from October to mid-December, while February to May give the calmest water.
Check your health first
Scuba needs a minimum level of health and fitness. Chronic conditions, certain medications or recent surgery may require written approval from a physician. Download the Diver Medical form and review it before you enrol.
Do not ask instructors or shop staff for medical advice, because only medical professionals can clear you to dive.
Best dive sites
Twins, beside Koh Nang Yuan, dives from 5 to 19 m and is rated Easy. It is about 10 minutes by boat from Mae Haad and works in almost any conditions all year. Pick it for first dives and training.
Sail Rock
Sail Rock (Hin Bai) dives from 5 to 40 m and is rated Advanced. It stands alone in open water between Koh Tao and Koh Phangan, and it is the one pinnacle that breaks the surface. The Chimney is a vertical swim-through that starts at 18 m, so you need confident buoyancy. It is a full-day trip at THB 4,000 per diver.
Chumphon Pinnacle
Chumphon Pinnacle dives from 14 to 36 m and is rated Advanced. It is a 45-minute boat ride north-west of the island, and the current can be strong. Whale sharks are seasonal and never guaranteed.
Best time to dive
Koh Tao is divable all year. February to May are the best months, with calm seas, 20 to 30 m and more of visibility and steady weather. June to September visibility is typically 15 to 25 m.
October to mid-December are the worst months, with choppy seas on north-shore sites and visibility down to 5 to 15 m on bad days. Many shops close for 2 to 3 weeks in mid-November, at the peak of the monsoon. Water stays between 28 and 30 degrees Celsius all year.
Protect the reef
A Department of Marine and Coastal Resources order protects marine and coastal resources around Koh Tao, Koh Phangan and Koh Samui. It aims to stop acts that cause serious damage to them. A separate order protects coral at underwater pinnacles in six provinces, including Chumphon and Surat Thani. Keep your fins off the coral and follow your guide.
Diving emergency: who to call
Save this number before you dive: the SSS chamber on Koh Tao answers on +66 81 081 9777. A second line is +66 77 427 427. The chamber sits at 1/124-1/125, Koh Tao, Surat Thani 84360.
Call, do not email.
Hyperbaric Services of Thailand runs the facility with a medical team on site and 24/7 cover. SSS also runs a chamber in Phuket for the Andaman coast.
Call the chamber first and do not wait to see whether symptoms pass. Keep the diver at rest, lying flat on one side. Give medical oxygen at the highest concentration you have. Early recompression gives the best chance of full recovery.
Hospital and ambulance
Ko Tao Hospital is a Ministry of Public Health service unit in Surat Thani province. For any medical emergency the national number is 1669.
Getting to Koh Tao
Lomprayah is the main high-speed operator on the Gulf, and it publishes a timetable for 2026. A catamaran leaves Pralarn Pier at 08:00 and reaches Koh Tao at 09:30 for THB 700. A slower ferry leaves at 11:00, arrives at 13:30 and costs THB 550.
From Koh Phangan, a catamaran leaves at 08:30, arrives at 09:30 and costs THB 600. A ferry at 12:00 arrives at 13:30 for THB 450. From Donsak Pier a catamaran leaves at 11:00 and arrives at 14:45 for THB 750.
Going back, a ferry leaves Koh Tao at 16:30 and reaches Koh Phangan at 18:10 for THB 450. Departures from Samui marked with an asterisk change onto a catamaran at Koh Phangan. Staff answer every day from 08:00 to 20:00.
Step by step
- Pick a course and a shopCompare the Open Water price and what it includes: THB 9,900 for three days at one school, THB 12,000 at others.
- Check your healthReview the Diver Medical form before you enrol; a physician may need to approve you.
- Time your tripAim for February to May for calm seas and visibility of 20 to 30 m.
- Save the emergency numberStore the chamber phone +66 81 081 9777 before your first dive.
Not confirmed: Shop prices move with the season and the package, so confirm the total and what it includes before you pay a deposit. Ferry fares from Chumphon are not confirmed here, so check the operator's page before you travel.
Common questions
How much does a PADI Open Water course cost on Koh Tao?
Isla Tortuga Divers charges THB 9,900 for three full days. Siam Scuba and Scuba Shack charge THB 12,000, and Scuba Shack includes materials, equipment, the PADI certification and the online manual.
How old do you need to be to learn to dive?
Anyone aged 10 or older can learn to dive. Junior Open Water Divers become Open Water Divers automatically at age 15. Children aged 8 or older can try scuba diving in a pool.
How deep can you dive with Open Water?
An Open Water certification lets you dive anywhere in the world up to 18 m.
When is the best time to dive Koh Tao?
February to May are the best months, with calm seas and visibility of 20 to 30 m and more. Koh Tao is divable all year.
Do you need a doctor's note to dive?
Chronic health conditions, certain medications or recent surgery may require written approval from a physician. Read the Diver Medical form before you enrol. Only a medical professional can give clearance.
What is the number for the Koh Tao recompression chamber?
Call +66 81 081 9777 in a diving emergency. A second number is +66 77 427 427. Call; do not use email.
Can you see whale sharks on Koh Tao?
Whale sharks are seasonal and never guaranteed at Chumphon Pinnacle. The best chances are March to May and September to October.
How do you get to Koh Tao?
A Lomprayah catamaran leaves Pralarn Pier at 08:00 and reaches Koh Tao at 09:30 for THB 700. From Donsak Pier it takes until 14:45 for THB 750.
Read next
Prices, timetables and opening hours change; check with the operator before you travel. See how guides are checked.
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