A school of yellowfin tuna feeding at the surface is one of the most arresting spectacles in saltwater fishing. The water boils white across fifty metres of open sea. Birds work overhead in tight spirals. Beneath the foam, the fish are moving as a unit — each one 20, 30, 40 kg of muscle, moving through the water faster than seems reasonable, driving bait against the surface until there is nowhere left for it to go. You cast, the popper lands in the carnage, and the strike arrives before you have completed the retrieve.
Yellowfin tuna (Thunnus albacares) demand to be taken seriously. They are strong in a way that goes beyond weight — the kind of strength that is systematic and relentless, that operates at maximum efficiency for the entire fight and seems to have reserves beyond what physiologically ought to be possible. They are intelligent enough to change the angle of their runs to maximise drag on the line, and fast enough to make any misjudgement of drag setting immediately consequential.
They are also available in Thailand's Andaman Sea to an extent that makes dedicated offshore trips consistently worthwhile, and they respond to multiple fishing methods, which means different styles of angler can find a common target.
Identification and Biology
The yellowfin is one of the larger tuna species and among the most distinctive in appearance. The bright yellow dorsal and anal fins, elongating to dramatic sickle-shaped extensions in large adults, make identification straightforward. The body is deep and fusiform, dark metallic blue above, silver-white below, with a golden-yellow lateral band running along the flank. The finlets between the second dorsal and tail are vivid yellow edged in black.
Yellowfin are highly migratory warm-water fish, following temperature gradients and the movements of prey through the Indo-Pacific. They are schooling animals, though school composition changes — juveniles school tightly in same-size cohorts, while larger adults form looser aggregations or associate with structure rather than schooling in the open water characteristic of smaller fish.
Growth is rapid in warm tropical waters. Fish can reach 20 kg within their first three years of life. Maximum size approaches 200 kg, though fish above 100 kg are rare in Thai fisheries. The species reaches sexual maturity at around 50 cm fork length and can live to six or seven years.
Where to Find Yellowfin Tuna in Thailand
The Andaman Sea holds the primary Thai yellowfin fishery, concentrated around several key habitat types.
FADs (Fish Aggregating Devices). Anchored offshore buoys and floating structures hold baitfish, and where baitfish concentrate, yellowfin follow. FADs positioned 20–60 km offshore of Phuket, Phang Nga, and Khao Lak are productive throughout the season, with school fish of 10–30 kg the typical catch. The fish around FADs are often the most accessible to day charter anglers.
Seamounts and offshore structure. The Burma Banks — a series of submerged banks in the northern Andaman — produce consistently larger fish and represent the benchmark destination for serious yellowfin anglers in Thailand. The outer Similan Islands, the deeper passages around Surin, and the seamounts that extend toward the Myanmar border all hold yellowfin, though accessing these requires liveaboard commitments of three to five days.
Weed lines and debris fields. During the northeast monsoon, floating debris accumulates in predictable patterns in the open Andaman, and yellowfin use these as meeting points. Captains who understand the current patterns of the season can locate fish at these ephemeral structures.
Yellowfin tuna behaviour around a FAD changes significantly with the tide and time of day. Early morning — first light to two hours after sunrise — typically sees the most surface activity. As the sun rises, fish move deeper. Plan your FAD arrival to coincide with first light, and have poppers and surface lures ready for the first hour before transitioning to jigging as the fish descend.
Season and Conditions
The northeast monsoon window (November–April) defines Andaman yellowfin fishing. January through March is typically the peak for larger fish, with water temperatures and baitfish concentrations aligning to hold fish around offshore structure. November and December often produce more numerous but smaller fish.
Sea surface temperature matters. Yellowfin favour water between 22–29°C, and in the Andaman the sweet spot tends to be around 28°C. A thermocline at 60–80 m depth is often associated with concentrated fish — they feed above it and retreat into cooler water when disturbed.
Techniques
Vertical jigging. The backbone of serious yellowfin fishing in Thai waters. Metal jigs in the 100–250 g range, worked either with high-speed jigging (consistent overhead retrieves) or slow-pitch (allowing the jig to flutter and fall), cover the water column where fish are holding. The jig choice — weight, shape, and colour — should be matched to current strength and the depth the fish are sitting. In strong current, heavier jigs maintain the vertical presentation essential to keeping the lure in the strike zone. Assist hooks on long split rings are standard.
Surface popping. The most visually spectacular method and one that demands physical commitment. Large cup-face poppers in the 80–180 g range, cast long and retrieved with hard, rhythmic rod pumps that drive the lure's face into the water and launch a spray forward, trigger explosive surface strikes from feeding fish. The retrieve is demanding — multiple hours of hard popping is physically taxing — but when fish are surface-feeding at dawn, the rewards are commensurate.
Stickbait fishing. Subsurface pencil stickbaits retrieved at speed produce fish when yellowfin are chasing prey just below the surface but not fully committed to feeding at the top. Stickbaits complement a popping approach, giving the angler a second option when surface presentations are being refused.
Trolling. Trolling with medium-weight skirted lures and cedar plugs at 7–10 knots produces yellowfin on Andaman transits and dedicated trolling runs. This is a consistent, if less exciting, method for covering ground and locating fish, and is the primary approach on some day charter trips that lack the liveaboard time for extended jigging.
Live bait. A live mackerel or flying fish fished beneath a FAD on a circle hook is one of the most consistently productive approaches for larger yellowfin in concentrated populations. The bait is fished on a long dropper from the surface, or with a small float to keep it at a specific depth.
A yellowfin tuna does not give up. It does not tire in the way most fish tire. What changes over the course of a long fight is not the fish's strength but your own — which is, in the end, the entire point.
Tackle
Jigging: PE 3–6 (approximately 40–80 lb) braid on a high-quality spinning reel with a smooth, powerful drag — this is not the application for underpowered equipment. Rods of 1.7–2.0 m in a medium-heavy to heavy action, designed for 60–200 g jigs, are the standard. Leaders of 60–100 lb fluorocarbon in 1.5–2 m length. Drag set at 40–50% of line breaking strength is appropriate for fish in the 20–40 kg range.
Popping: PE 6–10 (approximately 80–130 lb) braid on a large, powerful spinning reel. Popping rods of 2.3–2.6 m in extra-heavy action, rated for lures of 60–200 g, transfer the energy of the hard popping retrieve to the lure effectively and have the backbone to lift heavy fish away from structure on the strike. Leaders of 80–130 lb fluorocarbon.
Trolling: 30–50 lb class conventional outfit with a 4/0–6/0 lever-drag reel. Monofilament or heavy braid of 50–80 lb. Short, stiff trolling rod with roller guides.
The quality of drag systems matters enormously for yellowfin fishing. Multiple long runs, sustained pressure, and the sustained heat generated in the drag over a long fight can cause inferior systems to fail or lose calibration. Reels designed specifically for heavy offshore use, with high-quality sealed carbon drag systems, are the appropriate tool.
Records and Sizes
The IGFA all-tackle record stands at 176.35 kg (388 lb 12 oz) from Cabo San Lucas — a figure that places the species firmly among the most formidable pelagic game fish in the world. Thai waters produce a different scale of fish: school yellowfin of 10–30 kg around FADs, and larger specimens of 40–70 kg from the Burma Banks and outer seamounts. Fish above 80 kg are caught in the region but are not routine catches.
A 30 kg yellowfin on PE 4 jigging gear is a full-commitment fight of 20–40 minutes. A 60 kg fish demands respect from any angler on any tackle.
Conservation
Yellowfin tuna are listed as Near Threatened on the IUCN Red List, with populations under pressure from commercial longline fishing throughout the Indo-Pacific. The sport fishing contribution to pressure is small relative to commercial harvest, but responsible practices remain important. In Thai waters, releasing fish beyond a single keep is the sound approach, and ensuring fights are conducted with tackle appropriate to the fish size — both to maximise survival rates on release and to avoid gear failure that can result in fish being lost with hooks and line attached — is a matter of both ethics and technique.
What Hooking One Feels Like
The strike of a yellowfin on a jig or popper is unambiguous. The rod loads without any preliminary — it simply doubles over, and you are immediately in a fight for control of the situation. The first run is powerful and sustained; 60, 80, 100 metres of line leaving the reel against a properly set drag, with nothing you can do to slow it.
What distinguishes yellowfin from nearly every other Thai offshore species is what happens after that first run. The fish does not stop. It continues at a level of sustained output — circling deep, pulling against the drag in long, grinding arcs — that seems to defy reasonable assumptions about what a fish can sustain. The fight becomes, in part, a test of angler fitness and technique. Pumping efficiently, not wasting energy on wild cranking, keeping the rod loaded and working in short, controlled lifts, breathing — these things matter when a fish is taking everything you have.
When a yellowfin finally tires and comes up — large, deep-bodied, extraordinary in colour, the yellow fins bright as paint — you understand completely why anglers build entire offshore fishing programmes around this species.
Continue with the Andaman's offshore fishery in our guides to dogtooth tuna, deep-water jigging in Thailand, GT popping in the Andaman, liveaboard fishing in Thailand, and the 7-day Andaman fishing itinerary.
