Heavy rain flooded parts of Koh Samui on Thursday 12 November 2026, and Koh Samui police asked residents and tourists to delay non-essential trips. The Thai Meteorological Department warned of heavy rain and rough seas in the Gulf on 12 and 13 November. Explera DMC Thailand sets out what was reported, what was not, and what agents should reconfirm.
Explera handles ground arrangements as a Thailand DMC for travel agents. Its Thai company, Explera DMC Co., Ltd., holds TAT licence 14/05119, the Tourism Business Licence issued by the Department of Tourism, and the group is IATA TIDS-registered (96215733) and a member of ASTA (900408341). Write to b2b@explera.co.th.
What happened on Koh Samui on 12 November?
The Nation reported that at 8:28am on 12 November Koh Samui Police Station said water covered the road outside the Koh Samui City Municipality offices. Police asked residents and tourists to put off non-essential journeys. The rain eased by late morning, but police kept the advice in place. The municipality closed the Chaweng Canal sluice gate to stop seawater flowing back into low-lying areas, and ran large pumps to move water out to sea. The report does not say how far the water spread beyond that road.
One day earlier, on 11 November, the Department of Disaster Prevention and Mitigation (DDPM) sent mobile-phone alerts to Koh Samui and Koh Phangan districts, and to Thung Tako in Chumphon. They warned of flash floods, landslides and standing water.
What was reported about flights, ferries and roads?
The two Nation reports we read, dated 11 and 12 November, do not mention Samui Airport, ferry services or any road closure other than the flooded road by the municipal offices. Koh Tao is not named in the DDPM alert. We found no dated report of cancelled flights or ferries for these two days, so we do not say any were cancelled, and we do not say none were. The weather warning for 12 and 13 November forecast waves of two to three metres in the Gulf from Nakhon Si Thammarat southward, higher in thunderstorms, and told small boats in the lower Gulf to stay ashore. Ask the airline and the ferry company for the status of each sailing and flight.
Why is November the wet month on the Gulf side?
The Gulf islands get their heaviest rain late in the year, when the northeast monsoon blows across the Gulf of Thailand. Published climate averages for Koh Samui usually show October to December as the wettest months, with November most often the peak. The warning of 12 November named the same cause: a strong cold air mass from China and a moderate northeast monsoon. Our Koh Samui destination guide covers the island season by season.
What should agents do with clients on Samui, Phangan and Tao?
A guest already in a hotel needs a short message: follow local advice and avoid flooded roads. A guest with a ferry, a flight or a boat trip in the next few days needs a checked plan. Leave the most time between a ferry and an onward flight, because sea crossings are the first thing rough weather stops. Our post on Thai weather warnings explains who issues each warning and what it changes. If you book through a Thailand DMC, ask its ground team how the roads are that day. Our transport team can re-time transfers when a sailing moves.
What should you reconfirm before a client travels?
Check four things. First, whether the Thai Meteorological Department has issued a new warning after 13 November. Second, the ferry or flight on the day of travel, with the operator. Third, the road between the pier or airport and the hotel, with the hotel or your Thailand DMC. Fourth, what the client's travel insurance says about weather delays. Our duty of care playbook shows how to record what you told the client and when.
Next steps
Send us the names, hotels and travel dates of clients on the Gulf islands through our contact page. The trade desk replies within 24 hours, and the rest of what we do is on our Thailand DMC services page.
Sources
- The Nation, 12 November 2026: Koh Samui flooding prompts travel alert and emergency drainage
- The Nation, 11 November 2026: Flood alerts issued for Koh Samui, Koh Phangan in Surat Thani and Thung Tako in Chumphon
- Thai Meteorological Department: current warnings
Frequently asked questions
Was Koh Samui flooded on 12 November 2026?
Parts of it were. Police reported water over the road outside the Koh Samui City Municipality offices at 8:28am and asked people to delay non-essential trips. The report does not say how wide the flooding was.
Were Samui flights or ferries cancelled?
The reports we read from 11 and 12 November do not mention flights or ferries at all. We found no dated report of cancellations and cannot confirm there were none. Check each flight and sailing with the operator.
Is November a bad month to sell Koh Samui?
It is the wettest month on the Gulf side in most climate tables, because of the northeast monsoon. Clients can still travel, but the itinerary should leave room to move boat days.
Should a client cancel a Koh Samui trip because of the alert?
The police advice of 12 November was about non-essential local journeys on the island, not about travel to Samui. Check for a new weather warning, reconfirm the crossing or flight, and read the booking and insurance terms before changing anything.
