March is the shoulder of Thailand's high fishing season — not quite January's pristine peak, not yet April's punishing heat. The Andaman is still very much open for business, the Gulf improves sharply, and the freshwater scene remains productive if you time your sessions correctly. But signals are gathering. The days are getting longer and warmer. The monsoon is still months away, yet the atmosphere is beginning its slow pressurisation. Fish while the fishing is this good.
The Weather and Water This Month
March marks the beginning of Thailand's hot season. Bangkok climbs steadily, with daytime temperatures regularly reaching 34–36°C by mid-month. Nights no longer offer the relief they did in January. Humidity begins creeping back, and the cool-dry season's benign grip starts loosening.
The Andaman coast — Phuket, Krabi, Khao Lak — remains largely calm, but the first ripples of the pre-monsoon transition are sometimes felt in late March. Afternoons can build to short, sharp thunderstorms. Mornings remain ideal and offshore conditions are still classified as high season by most charter operators. Water temperature offshore rises to 29–31°C.
The Gulf of Thailand improves dramatically through March. The northeast monsoon's influence fades, and the Gulf's eastern side around Koh Samui and Koh Tao settles into its most fishable window of the first half of the year. This is an underrated month on the Gulf.
In the north, March is warmer and drier than February, and highland reservoirs begin their pre-monsoon phase. Water temperatures rise, fish behaviour shifts, and the prime window for northern reservoir trips is genuinely narrowing.
Dawn or bust in Bangkok
By late March, Bangkok pay-lake sessions that start after 10 a.m. are increasingly uncomfortable. Experienced local anglers fish from first light and are packing up by midday. Plan accordingly.
Freshwater Fishing This Month
Bangkok Pay-Lakes
The pay-lake scene in Bangkok operates through March with no interruption, but the comfort calculus changes. Early-morning sessions — 6 to 11 a.m. — remain productive and pleasant. The fish are feeding actively before the heat peaks. Afternoon fishing becomes increasingly unpleasant by late month, with direct sun turning uncovered bank pegs into something approaching an endurance test.
Bungsamran Lake is still producing well. Giant Mekong catfish and giant Siamese carp remain the targets for most visiting anglers. March water temperatures in stocked lakes are in the high twenties — fish metabolism is rising, and feeding windows are often intense but shorter than the all-day affairs of January.
IT Lake Monsters runs its own schedule, and the arapaima and alligator gar don't care about the heat in the same way warm-blooded anglers do. Exotic Fishing Thailand and Dreamlake Fishing Resort both offer covered or partially shaded pegs — worth prioritising for March sessions.
For giant snakehead in Bangkok's canal network, March mornings see the species actively hunting. Surface lures at dawn, before the water warms, produce better results than midday attempts.
Northern Reservoirs — Last Call
This is effectively the last reliable month for northern reservoir trips. The highland lakes and rivers are warming, and the clarity and fish concentration that made January and February so productive will diminish as March progresses and April arrives.
Mahseer fishing in particular is window-closing. These fish are sensitive to water temperature and clarity changes. A March trip to the Chiang Mai or Mae Hong Son river systems, timed for the first two weeks of the month, can still deliver excellent fly-fishing. Wait until April and the experience is considerably diminished.
Gillhams Fishing Resort in Krabi continues operating year-round. Its managed lake system is more insulated from seasonal temperature swings than wild river systems, making it viable well into the warmer months for those who want the mahseer experience alongside Andaman saltwater access.
March is the month that rewards the angler who commits early — to the Andaman, to the north, to the 6 a.m. alarm.
Saltwater Fishing This Month
Andaman Sea
The Andaman Sea in March is still excellent, though the calendar is ticking. Sailfish continue to show well on offshore grounds. Charter operators from Khao Lak and Phuket maintain active schedules, and the Burma Banks liveaboard circuit is running at full capacity through much of the month.
Sailfish numbers are slightly past their absolute peak but remain highly fishable. The biology of the migration means that late-season fish are often individual, larger specimens rather than the schooling groups of February. For a serious angler targeting a trophy-sized fish, March can outperform the numbers-heavy days of peak season.
GT popping at the Similans and outer reefs remains very good in March's warm, clear water. Giant trevally are hungry and aggressive around structure. This month, the water temperature bump actually helps surface-lure fishing — fish are more surface-oriented in warmer conditions.
Deep water jigging around Andaman seamounts is productive for amberjack, dogtooth tuna, and various large-bodied reef species. As Andaman charters begin their seasonal wind-down toward May, some operators concentrate on jigging as a reliable alternative to offshore trolling.
Koh Rok south of Krabi is accessible on day trips from Krabi town and remains a good option for sailfish outside the fully booked Khao Lak circuit.
Gulf of Thailand
March is arguably the Gulf's best month of the first half of the year. The Gulf of Thailand fishing scene, centred on Koh Samui, Koh Tao, and the Chumphon area, sees stable warm conditions and productive reef fishing. Barramundi, Spanish mackerel, and reef snapper are reliable targets.
Sportfishing out of Koh Samui picks up significantly. Pelagic fishing — trolling for wahoo, mahi-mahi, and king mackerel — improves as the Gulf warms. This is a genuine option for anglers who are in the Gulf region and don't want the crowded and expensive Andaman circuit.
The Gulf of Thailand fishing guide is worth reading before committing to Gulf-based trips.
Recommended Trips This Month
1. Last Andaman Liveaboard of the Season — Book a Burma Banks liveaboard in early to mid-March before operators scale back. Combine GT popping at the Similans with billfish trolling. This is the last comfortable window before pre-monsoon conditions begin building.
2. Phuket Jigging and Popping Day Charter — A full-day charter out of Phuket targeting GT and deep-water species on Racha Yai and Racha Noi is excellent value in March and doesn't require the liveaboard commitment.
3. Northern Mahseer Fly Trip — Early March Only — Fly to Chiang Mai in the first ten days of March and spend three days with a highland guide targeting mahseer on fly gear. This window is genuinely closing.
4. Gulf Sportfishing from Koh Samui — If the Andaman is fully subscribed, base yourself at Koh Samui and fish the Gulf for pelagics. Underrated in March, often available at short notice.
What to Avoid This Month
Avoid midday to early-afternoon freshwater sessions in Bangkok without substantial shade. The heat that arrives in late March is real and affects both angler comfort and catch rates. Early morning is the operating window.
Don't assume Andaman liveaboards have availability in March without checking. February overflow continues into early March, and good operators are committed well ahead. Budget operators with available slots may have available slots for a reason.
Avoid planning a casual northern reservoir trip without confirming current conditions with a local guide. March weather in the north can vary significantly, and the difference between a superb and a disappointing mahseer session often comes down to very specific water temperature and clarity conditions.
Comfort and Gear Notes
Heat management begins to matter in March. Sun protection clothing is no longer just advisable — it's mandatory for extended outdoor sessions. A good buff, lightweight sun shirt, and wide-brimmed hat are your primary defence.
Hydration is also more critical than in the cool season months. Bring significantly more water than you think you need for morning sessions. Electrolyte sachets are a practical addition to your kit.
For freshwater, check our siamese carp rigging guide if you're targeting the big cyprinids at Bangkok lakes. For saltwater jigging on the Andaman, the saltwater jigging rods Thailand guide covers equipment in detail.
Where to Go Next
April transforms the experience significantly — Songkran mid-month, serious heat, and the beginning of Andaman operator wind-downs. See our April fishing guide for how to navigate the hottest month of the year.
For context on what the cool season offered before March, see February and January. The monsoon season fishing strategy guide is worth bookmarking now — you'll need it in two months.
