The Final Chapter of the Blue-Water Season
There is a particular quality to Andaman fishing in April — a sense of season's edge, of making the most of conditions before the calendar turns against you. The southwest monsoon is coming. Every experienced angler and every captain running charters out of Phuket, Khao Lak, and Krabi knows it. The question is not whether conditions will change but when, and seasoned operators read the sky, the barometer, and the sea with an attention to detail that sharpens as April deepens.
For those who catch the month early, the rewards can be exceptional. The Andaman's blue-water conditions in the first three weeks of April represent some of the finest offshore fishing available anywhere in the region. Surface temperatures remain warm, baitfish are abundant, and the pelagic species that congregate along thermocline edges and offshore structure have had months of settled conditions to establish patterns.
April is the Andaman's swan song. Anglers who have been waiting for the "right time" to book a Similan live-aboard or a blue-water charter out of Phuket should not wait further — by mid-May, most operations will have suspended offshore departures.
Sailfish and Billfish at Season's Peak
The waters between the Similan Islands and the outer Andaman banks continued to produce sailfish encounters through April, with captains running trolling spreads reporting consistent raises on smaller skipjack and mackerel-pattern lures. The sailfish population off Thailand's Andaman coast peaks in the final months of the dry season as bait schools concentrate in preparation for the shift in current patterns that the monsoon brings.
Wahoo and dorado were also prominent in the offshore catch reports, with trolling along current edges and colour changes accounting for multiple fish on longer day trips. The dorado in particular showed in good numbers around floating debris lines — a reliable indicator that bait was stacking up ahead of the seasonal transition.
For those targeting billfish specifically, the deeper-water areas west of the Similans and along the northern banks remained most productive. Captains running these grounds reported better results in the first half of the month, with consistency becoming patchier as April's second half brought increasing afternoon cloud build-up and the first hints of the monsoon's approach.
GT Popping Around Island Structure
Inshore, the rocky headlands and island edges of Phang Nga Bay and the waters around Krabi continued to give up giant trevally to surface poppers and stickbaits worked during the early-morning and late-afternoon windows. April's calm conditions made these areas accessible that would be unfishable once the monsoon swell arrives, and the GT action — while never guaranteed — rewarded persistent anglers with proper technique.
The Andaman's GT fishing is at its most accessible in April. Flat seas bring structure within reach that spends six months under monsoon swell. For surface-lure enthusiasts, this is the month to be here.
Jigging anglers working deeper reef structures adjacent to the islands also found consistent action on grouper, amberjack, and ruby snapper. The clear, settled water allowed jig presentations to work effectively at depth, and the absence of monsoon currents made station-keeping straightforward for captains.
Similan Operations: Plan Ahead
Charter operators offering trips to the Similan Islands National Park were still running in early April, though the scheduling was tightening as the month progressed. Live-aboard operations that form the backbone of Similan fishing access were monitoring conditions carefully, with some operators adjusting itineraries to spend more time in sheltered island groups and less time on fully exposed offshore banks.
Anglers planning to include Similan access in their trip should confirm current operational status directly with operators rather than assuming availability based on standard season dates. The monsoon's timing varies year to year, and responsible charter companies will prioritise passenger safety over schedule — sometimes resulting in last-minute adjustments that affect fishing itineraries.
The Last Good Weekend
Toward the end of April, the character of the sea begins to change in ways that Andaman regulars recognise immediately. The horizon loses its sharpness. Afternoon cloud builds earlier. The swell that arrives overnight takes longer to settle by morning. The fishing does not stop — but the certainty of a comfortable day afloat becomes less reliable.
This transitional period produces its own rewards for those willing to tolerate variable conditions. Pelagic fish can feed aggressively as pressure systems move through, and some of the month's best catches have come during the window between one weather system passing and the next arriving. Experienced captains exploit these windows efficiently, which is another reason to choose operators with long track records on these grounds.
What to Expect in May
Most offshore charter operations will suspend or significantly reduce activity as the southwest monsoon establishes in May. The Andaman coast pivots toward monsoon-adapted fishing — some inshore options remain viable from sheltered harbours — but the blue-water season is effectively over.
Anglers looking to continue their Thai fishing trip into May should plan to relocate to the Gulf of Thailand side, where the monsoon's effect is less direct and offshore conditions remain manageable through most of the month. The Gulf coast from Hua Hin south through Chumphon offers a workable alternative that sees improved conditions precisely as the Andaman closes down.
Recommendations for Visiting Anglers
Book early in the month and treat anything after the 20th as weather-dependent. April on the Andaman is a month of diminishing windows — the earlier in the month you fish, the more consistent your conditions will be.
Discuss the weather outlook with your captain or operator the evening before any offshore trip. Experienced Andaman guides watch forecasting models daily through this period and will have a clearer picture of the following day's conditions than any general travel advisory can offer.
For those with flexible itineraries, consider a mixed-approach week: blue-water charter in the first half, inshore GT and reef fishing in the second. This hedges against the weather becoming less cooperative while ensuring you experience both sides of what the Andaman offers at its best.
