When can you actually do a Phuket boat tour? Almost every month of the year. What changes in the rainy season is the route, not whether we sail. From May to October the southwest monsoon makes the Andaman Sea less predictable, so we lean on sheltered water like Phang Nga Bay, keep island plans flexible and make the go/no-go call on the morning's real conditions. Here's how the year behaves on the water, month by month, from an operator that has been running boats out of Phuket since 2005.
Phuket rainy season months: what the sea actually does
Phuket's rainy season runs roughly May to October, when the southwest monsoon pushes wind and swell in from the Indian Ocean onto the island's exposed west coast. The dry season, November to April, is the opposite: light winds, flat water, clear visibility and every route on the map.
The thing most weather apps won't tell you is that rain isn't the problem on a boat; swell is. A typical green-season day brings a shower that rolls through for 30–60 minutes and clears. That's a non-event when you're already wet from snorkelling. What decides whether a day is smooth or lumpy is the wind and the sea state, and that varies a lot by direction. Water tucked behind limestone, like Phang Nga Bay north-east of Phuket, can be calm on a day when the open run towards Phi Phi is rough.
So "is it the rainy season?" is the wrong question. The useful one is "which water is good today?" Answering that every morning is our job.
Month by month: the boat-tour calendar
| Month | Sea conditions (typical) | What runs well | Worth knowing |
|---|---|---|---|
| January | Calmest of the year, very clear water | Everything: Phi Phi, Phang Nga, Krabi, southern islands, sunset trips | Peak demand. Book ahead. |
| February | Calm, dry, reliable | Everything | Still peak season. |
| March | Calm, getting hotter | Everything | Early departures beat the midday heat. |
| April | Calm mornings, hot, the odd pre-monsoon storm late in the month | Everything; Sunset Shark's last month | Songkran mid-month = busy roads, easy seas. |
| May | Transition: the monsoon arrives, mixed days | Phang Nga Bay, Phi Phi on good days, private charters | Sunset Shark paused until November. Similan National Park closes (not an SST route). |
| June | Mixed, plenty of good windows | Phang Nga Bay, Phi Phi Sunrise, Locals Island | Quietest islands of the year begin. |
| July | Variable, breezier | Phang Nga Bay is the most reliable choice | Confirm ambitious plans close to the date. |
| August | Variable | Phang Nga Bay; Phi Phi Sunrise runs with Bamboo Island in place of Maya Bay | Maya Bay's annual national-park closure (Aug–Sep). |
| September | Most unpredictable seas of the year | Phang Nga Bay; shorter, flexible days | The month we cancel or swap routes most often. Keep a spare day. |
| October | Still unsettled, improving late in the month | Phang Nga Bay; Phi Phi as conditions allow (Maya Bay back from 1 Oct) | Late October often feels like November arriving early. |
| November | Settling into dry season | Everything; Sunset Shark returns | Crowds are back but not yet peak. |
| December | Calm, clear | Everything | Christmas–New Year is the busiest fortnight. Book early. |
This is the pattern, not a promise. Any single day in any month can be the exception, which is why the decision is always made on the morning, not on the calendar.
What runs in the rainy season (and what doesn't)
Phang Nga Bay: the green season's home ground. The bay is ringed by limestone karsts and mangroves that block most of the monsoon swell, which makes it the most dependable trip from May to October. Our Phang Nga Bay & James Bond Island tour runs year-round, and green-season light on the karsts is some of the best of the year. If you only have one boat day in September, this is the one we'd point you at. More on the area in our Phang Nga Bay destination guide.
Phi Phi Islands: yes, with a plan. The Phi Phi Sunrise Tour runs year-round. You leave Boat Lagoon Marina early, catch the sunrise at sea during the roughly 1hr 10min crossing, and reach the islands before the day-tripper fleet. That early start matters even more in the rainy season, because mornings are usually the calmest part of the day. In August and September Phi Phi National Park closes Maya Bay for ecosystem recovery, so we visit Bamboo Island instead (current Maya Bay rules here). On the roughest days we'll tell you honestly that Phi Phi isn't on and suggest Phang Nga instead.
Phi Phi Sunset & Shark: dry season only. The Sunset Shark tour runs November to April. Afternoon thunderstorms are far more likely in the wet season, and we don't schedule an evening open-water crossing into that risk.
Closer-to-home islands and private charters. The Locals Island tour (larger boat, maximum 25 adults) and our private charters give the most flexibility in the green season. With your own boat we can re-shape the day around the weather, moving stops, swapping a snorkel site for a sheltered beach, or switching the whole route to Phang Nga.
What we don't run: the Similan Islands. The Similan Islands National Park closes every year from mid-May to mid-October (dates here). Even in season, we don't run Similan day trips from Phuket, because the open-water distance makes for a long, exposed day that doesn't meet our own safety bar.
How we make the weather call
Every departure gets a go/no-go decision made on the morning's actual wind, swell and forecast, not the day before, and not on the booking calendar. Those calls follow written marine SOPs set by Paul Chappell, our Marine Base Captain, who has run commercial boat operations in Phuket since 2014 and spent 23+ years as a professional airline pilot, a career built on conservative, checklist-driven decisions. Our boats are run by experienced, locally licensed Thai captains who know this water better than any app. The rule they work to is simple: if a sea state is marginal, we change the route or we don't go.
What that means for you:
- Route swaps first. If the open water is rough but the bay is calm, we'll tell you before you leave the marina and offer the sheltered alternative.
- If we call the trip off for weather, your deposit is refunded in full, or we'll move you to another date if you'd rather.
- You can cancel free of charge up to 24 hours before departure. Full details are in our cancellation policy guide.
For the bigger safety picture (red flags on the beaches, what's actually risky in low season, how to judge an operator), read our honest guide to Phuket safety in low season.
How to book a rainy-season boat trip well
- Book early in your stay, not on your last day. That leaves room to move the trip if the sea says no.
- Choose morning departures. Green-season afternoons are when storms build.
- Pick the sheltered route if you're seasick-prone. Phang Nga Bay is the gentlest water in the region from May to October.
- Pack for wet, not for cold. Quick-dry clothes, a dry bag for your phone and reef-safe sunscreen. Cloud doesn't stop UV. (Our full packing list.)
- Small groups help. Our join-in boats carry a maximum of 18 adults, so there's room to move and the crew can adapt the day without herding a crowd.
If a properly grey day lands on you, here are rainy-day ideas around Phuket. Want to plan a charter around the season? Our charter season guide covers that. Still deciding when to come at all? Start with our month-by-month guide to the best time to visit Phuket.
The short answer
The rainy season changes the plan; it rarely cancels it. From November to April the whole Andaman is open. From May to October we sail sheltered water first, chase the good windows to Phi Phi, and make an honest call every morning. Browse our join-in tours or the full range of Phuket boat tours for your dates. Prices are all-inclusive, with national park fees already covered, and every trip leaves from Soho Pool Club at Boat Lagoon Marina.
