Is the Chumphon to Koh Tao crossing rough?
Sometimes, on a calendar that surprises people. Chumphon to Koh Tao crosses open Gulf of Thailand water in about 2 hours on Lomprayah and Songserm catamarans, and its rough season is the opposite of Phuket's: here the north-east monsoon from November to January makes the waves, while the Andaman coast's rough months are this coast's calm ones.
Gulf of Thailand · about 1 hour 45 minutes to 2 hours by catamaran · Reputation among passengers: mixed: commonly reported as uncomfortable in the wrong conditions.
Service status, September 2026
Songserm's slow boat could not be confirmed for 2026 and its websites are offline. Lomprayah catamarans sail from Thung Makham Noi pier and Boonsiri from Matapon pier, about 2 hours.
- Low
- Moderate
- High
- Very high
Roughness summarises typical reported conditions on this route, not a forecast for any given sailing.
Gulf chop on the opposite monsoon calendar
Key facts
- The Chumphon to Koh Tao crossing takes about 1 hour 45 minutes to 2 hours by catamaran, operated by Lomprayah and Boonsiri.
- It crosses the Gulf of Thailand, and passenger reports place the route in the moderate roughness band.
- What drives the rough days: Gulf chop on the opposite monsoon calendar.
- Conditions are reported roughest in January, November and December.
- The calmest months are usually March, April and May.
Taking the Chumphon to Koh Tao crossing? Dizzout is drug-free sound therapy you can start in your seat on the crossing, with relief in about 90 seconds.Starts in your browser · works with any headphones
Stop seasickness. Get your personalized Dizzout plan. Paid subscription for full access.
On your phone? Scan to start there.
Why the Chumphon to Koh Tao crossing gets rough
The Gulf's east-facing coast catches the north-east monsoon, which blows from November to January and builds short, steep gulf chop across the open crossing. High-speed catamarans meet it with rapid pitching, and the divers' forums fill with rough-crossing stories every season. From roughly February to October the gulf is mostly settled, with the south-west monsoon spending its energy on the other coast.
When it's worst, month by month
November to January is the rough window; February to October is mostly settled, which is the reverse of the Andaman coast's calendar and worth planning around.
| Roughest water in Jan | Roughest water in Feb | Roughest water in Mar | Roughest water in Apr | Roughest water in May | Roughest water in Jun | Roughest water in Jul | Roughest water in Aug | Roughest water in Sep | Roughest water in Oct | Roughest water in Nov | Roughest water in Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Rough | Mixed | Calm | Calm | Calm | Mixed | Mixed | Mixed | Mixed | Mixed | Rough | Rough |
Typical seasonal pattern, not a forecast. Any month can deliver a calm crossing or a bad one. Check the marine forecast for your sailing date. Select a month to see every sea and ferry crossing ranked for it.
Month bands: Dizzout sea-state data for the Chumphon to Koh Tao crossing, built from the reports and sources listed on this page. Free to cite with a link to this page.
Where to be on board
Front to back
- Front rowsAvoid
- Central, low deckBest
- Rear rowsOK
The crossing: about 2 hours
Roughest stretch: Open gulf water, most of the crossing
Central seats on the lower deck of the catamaran; the front rows over the bows take the monsoon chop hardest.
Which boat to pick
The slower boats ride marginally softer but take much longer; in the north-east monsoon the practical levers are the date, the morning departure and a central seat, more than the vessel.
Taking the Chumphon to Koh Tao crossing? Have Dizzout ready
Stop seasickness
Dizzout is drug-free sound therapy you can start in your seat on the crossing, with relief in about 90 seconds. It plays precisely calibrated audio through any headphones you already own, wired or Bluetooth. Free to download.
Get your personalized Dizzout plan. Paid subscription for full access.
30,000+ travelers in 30+ countries · How we count
On your phone? Scan to start there.
Comparing apps first? See how the motion sickness apps compare
Not travelling yet? Remind me the day before my trip
Know someone who gets motion sick?
Send them the app that helps stop it, drug-free, in about 90 seconds, works with any headphones. Free to download.
What helps on this crossing
- Travelling November to January, book the earliest departure; the monsoon wind builds during the day.
- Sit central and low, horizon through the windows, phone away.
- Keep the pre-boarding meal light in monsoon season; two hours of pitching is easier on an empty-ish stomach.
- Divers on a schedule should pad travel days in the rough window; sailings do get re-timed.
- Dizzout, a drug-free sound therapy app for passengers: it works with any headphones once nausea starts, with relief in about 90 seconds.
For the full toolkit see the seasickness guide, or what to do once it has already started. Choosing between a fast catamaran and a conventional ship elsewhere too? The physics is the same everywhere: see the catamaran guide. If the rocking follows you ashore afterwards, that is land sickness, which is normal, and it passes.
Frequently asked questions
Is the Chumphon to Koh Tao ferry rough?
From November to January, often: the north-east monsoon builds steep gulf chop and the catamarans pitch through it, which is when most of the rough-crossing stories are written. From roughly February to October the gulf is mostly settled and the crossing routine.
How long does Chumphon to Koh Tao take?
About 1 hour 45 minutes to 2 hours on the high-speed catamarans from Lomprayah and Songserm, connecting with buses and trains at Chumphon; slower boats also serve the island.
Why is this coast rough when Phuket is calm?
Thailand's two coasts sit on opposite monsoons: the south-west monsoon (May to October) batters the Andaman side while the gulf stays workable, and the north-east monsoon (November to January) reverses it. Route-planning around that swap is the single best trick for queasy travellers in Thailand.
Seasickness medicine for the catamaran: yes or no?
In the monsoon window, worth asking a pharmacist about before you travel; motion sickness medicines are generally labelled for use before boarding. Outside it, most passengers are fine with a sensible seat and a light breakfast.
Other ferry routes
Sources & further reading
Your next question, probably
Where on the ship should you be?
Which cabins move least, and what to do if you already booked one
Not your question? What actually works at sea?Sick right now, mid-crossing?Still rocking after you land?
Conditions described here are typical patterns drawn from published marine and operator information as of September 2026, not a forecast: any month can deliver a calm crossing or a bad one, and schedules, vessels and operators change. Route, vessel and operator names are trademarks of their respective owners; Dizzout is not affiliated with or endorsed by them. Seasickness sensitivity varies from person to person; this page is informational and not medical advice.