Monday3 dives
1× Koh Bon and 2× Similan #9
Divers only
Base trip price6,300 THB
Diving Season Guide
When Is the Best Time to Dive in Khao Lak and Thailand?
Plan your Thailand dive trip around the right season, route, and conditions. Dive Syndicate helps guests match travel dates with Khao Lak local dives, Similan Islands day trips, Richelieu Rock, beginner courses, and professional SSI training.
The Planned Offshore Week
The weekly plan runs from 15 October 2026 to 15 May 2027. Routes can change with weather, ticket availability and diver experience.
Tuesday2 dives
Similan #4 and #5
Divers and snorkellers
Base trip price5,300 THB
Wednesday2 dives
2× Richelieu Rock
Divers only
Base trip price5,500 THB
Thursday2 dives
Koh Tachai
Divers only
Base trip price5,300 THB
Friday2 dives
Similan #8 and #9
Divers and snorkellers
Base trip price5,300 THB
Saturday2 dives
2× Richelieu Rock
Divers only
Base trip price5,500 THB
Sunday2 dives
Similan #7
Divers and snorkellers
Base trip price5,300 THB
MondayAuto-advances every 6 seconds
Dive sites can change without prior notice depending on weather conditions, ticket availability, and diver experience levels.
Quick Answer
There Is No Single Best Thailand Diving Season
The best diving season for Khao Lak, the Similan Islands, Richelieu Rock,Koh Bon manta season,Koh Tachai conditions, and the northern Andaman Sea depends on marine park schedules, weather, and sea conditions. Travellers should confirm availability for their exact dates before booking, especially for offshore day trips.
Month and Season Overview
How to Think About the Khao Lak Diving Calendar
Exact marine park opening dates and routes can change, so this overview should be treated as planning guidance. Always confirm current schedules before booking.
Main planning window
November to April
This is the usual core period guests associate with Khao Lak offshore diving, including Similan Islands and Richelieu Rock routes when schedules and conditions allow.
Peak demand
December to March
A popular time for travelling divers. Book early, share your experience level, and confirm route suitability before committing to famous offshore sites.
Shoulder months
October, April and May
Availability can be more variable around season edges. These months require direct confirmation for marine park access, weather, and route schedules.
Green season planning
May to October
Offshore route availability is more limited and weather can be less predictable. Some training or Boonsung Wreck local diving may still be possible depending on schedules and conditions.
Why Season Matters
Conditions Change the Right Dive Plan
Diving conditions are not the same everywhere in Thailand at the same time. Khao Lak and the northern Andaman Sea are strongly affected by marine park schedules, monsoon patterns, wind, waves, currents, and visibility.
Marine parks
Offshore Routes Are Seasonal
Similan Islands, Richelieu Rock, Koh Bon, Koh Tachai, and Surin Islands season routes depend on park rules, schedules, weather, and operational availability.
Daily decisions
Weather and Sea State Matter
Wind, waves, current, visibility, and official restrictions can change the best route even during the main season.
Right fit
Beginner Suitability Changes
A route that is comfortable on one day may not be suitable for a newer diver on another day. Direct planning prevents wrong-trip bookings.
Routes by Season
Khao Lak, Similan Islands and Richelieu Rock
Khao Lak base
Local Dives and Training
Local diving can be useful for refreshers, check dives, relaxed guided dives, training days, and candidates starting professional training.
Khao Lak diving guideSeasonal offshore
Similan Islands
Similan Islands diving from Khao Lak should always be confirmed for your exact travel dates. Route choice can change because of weather, current, visibility, or official restrictions.
Similan Islands diving day tripConfident divers
Richelieu Rock
Richelieu Rock is an offshore site and should be treated as a planned day-trip objective, not a guaranteed everyday route.
Richelieu Rock from Khao LakBeginner Suitability
Do Not Choose a Trip Only Because It Is Famous
Beginners can dive in Khao Lak when the route, conditions, and supervision are suitable. Uncertified guests should start with Try Scuba or SSI Open Water Diver training rather than booking certified fun dives.
Ask first
Better Planning Questions
- Are you certified?
- When did you last dive?
- Are you comfortable in open water?
- Do you need a refresher?
Easier first day
Local Before Offshore
A local dive, check dive, or refresher can be a better first step than jumping straight into a famous offshore route.
Compare guided dive optionsNot certified yet
Start With Training
If you are new to diving, plan Try Scuba or Open Water Diver training before choosing certified fun dives.
Start diving in Khao LakMarine Life Highlights
What You May See in the Andaman Sea
Marine life is never guaranteed. Season, site, current, visibility, water movement, and luck all affect what divers see.
Reef Life
Reef fish, turtles, moray eels, and busy coral scenes are common highlights across suitable Andaman Sea routes.
Schooling Fish
Offshore routes can offer schooling fish and wide blue-water scenes when visibility and conditions are favourable.
Macro Life
Slower dives and local routes can reveal nudibranchs, shrimp, scorpionfish, and other smaller reef subjects.
Seasonal Pelagic Chances
Larger encounters are possible seasonally, but responsible operators should never sell them as guaranteed.
Pricing and Trip Planning
Use Season Advice to Build the Right Quote
Season pages should lead into direct enquiry rather than listing every possible route. The final plan depends on your dates, certification, route availability, equipment needs, park fees, and current conditions.
Day trips
Offshore Starting Prices
- Similans / Koh Tachai, 2 dives: 5,300 THB base price
- Richelieu Rock 2 dives:5,500 THB base price
- Koh Bon / Similan 3 dives:6,300 THB base price
Local option
Khao Lak Local Diving
- Sea Chart / Premchai Wreck:3,800 THB
- Boonsung Wreck / Wreck Park T-13: 3,500 THB
- Khao Na Yak Reef: 3,000 THB
Additional
Confirm Before Booking
- Offshore National Park entry: 500 THB
- National Park diving fee:200 THB
- Optional rental equipment:500 THB
Offshore park entry, diving fees and optional rental equipment are separate from the base price. Local rental equipment is optional at 500 THB and excludes a dive computer.
Why Book Direct
Dates Matter. Book With the Team Planning Your Trip.
When you book direct, the Dive Syndicate team can check your travel dates against current schedules, route availability, certification level, recent experience, equipment needs, and accommodation area before recommending a plan. This reduces the risk of booking the wrong destination, wrong difficulty level, or wrong schedule through a third-party listing.
Diving Season FAQ
Practical Answers Before You Book
The best time depends on marine park schedules, route availability, weather, and sea conditions. Always confirm your exact travel dates before booking offshore trips.