Gulf of Thailand ferry weather
Check waves, wind and thunderstorms across the Gulf of Thailand today and tomorrow, with guidance for ferries and fast craft around Koh Samui, Koh Phangan and Koh Tao.
The Gulf has a different seasonal pattern from Thailand's Andaman coast. Check the live marine outlook, vessel type and operator before departure.
Gulf of Thailand outlook
Waves to 0.1 m · 12 kt winds · gusts 15 kt
Calm outlook for most ferry passengers.Waves to 0.2 m · 13 kt winds · gusts 18 kt
Calm outlook for most ferry passengers.Currently looking broadly similar to today and tomorrow.
5-day trend · Lower confidenceGenerally comfortable conditions on a conventional ferry.
The Gulf of Thailand has its own ferry-weather pattern
The Gulf of Thailand is home to a dense network of ferries and high-speed catamarans linking the mainland with Koh Samui, Koh Phangan and Koh Tao. These are relatively short island crossings compared with long overnight ferries, but the vessels are often smaller and more responsive to wind-driven waves.
The important point is geographic: weather on Thailand’s Andaman coast does not automatically describe the Gulf. The two sides of the peninsula can be under different wind and wave conditions at the same time.
Gulf of Thailand wave forecast
Use the map to compare the mainland approaches with the open water around Samui, Phangan and Tao. A sheltered pier can look calm even when the sea becomes more active a short distance offshore.
Late-year northeast monsoon weather can matter strongly in the Gulf
Thailand’s general rainy season begins around mid-May with the southwest monsoon, but the Gulf has an important second pattern later in the year. From around mid-October, the northeast monsoon begins to replace the southwest monsoon. After crossing the South China Sea and Gulf of Thailand it can bring wetter, windier conditions to southern Thailand’s east coast.
That means a simple “Thailand dry season” rule is not enough for Samui-area ferries. In November and December especially, stronger northeast-monsoon episodes can produce higher waves in the Gulf even when other parts of Thailand are becoming drier.
Southwest monsoon
Rain and thunderstorms are common, with periodic stronger wind and waves. Conditions can vary markedly from day to day.
Northeast monsoon builds
The east coast of southern Thailand can become wetter and the Gulf can see stronger wind-wave episodes.
Often more settled
The northeast monsoon generally weakens later in the season, although windy periods and local thunderstorms remain possible.
Thunderstorms matter
Short-lived squalls can temporarily create waves above the broader background sea state.
Where Gulf of Thailand ferry weather matters most
Lomprayah’s 2026 timetable shows multiple daily high-speed ferry connections across the Samui-Phangan-Tao network. The route can therefore offer several departure choices, but changing the departure time does not necessarily mean changing the sea state.
A short crossing can still feel lively on fast craft
Many Gulf routes use high-speed catamarans or smaller passenger vessels. Those craft can react quickly to short wind waves, so a crossing does not need very large swell to feel active. If several operators or departure types are available, vessel type can be as important as the headline wave height.
For a more detailed explanation, read the fast ferry versus large ferry guide and the seasickness guide.
Complete the Gulf of Thailand weather check
Use the live sea outlook first, then compare it with Thailand’s official shipping forecast and your operator’s current timetable.