Giant trevally have a reputation that precedes them. Among experienced saltwater anglers, the GT is discussed not just as a target species but as an experience in itself — a fish defined by its aggression, its power, and its complete indifference to the angler's wellbeing. In the Thai Andaman, this reputation is well-earned, and the fishery that surrounds the Similan and Surin Island chains, alongside the limestone structures of Phang Nga Bay and the outer reef systems, represents one of Southeast Asia's most consistent and accessible GT popping destinations.
What Defines This Fishery
GT popping, in its pure form, is topwater fishing with heavy spinning gear and large surface lures worked fast and loud across the water. The method is intentionally provocative — mimicking a panicked, fleeing baitfish — and the GT's response is proportional. A proper GT strike on a topwater plug is not a subtle take. It is an explosion of water that can be heard from twenty metres away, followed by the first run of a fish that wants nothing to do with being caught.
What makes the Thai Andaman GT fishery distinctive is its geographic variety. You are not fishing open-ocean structure. You are fishing against and around limestone karst walls, rocky outcrops, island corners, deep channel edges, and current-swept points — the same dramatic physical environment that makes these islands famous for diving. The GT uses this structure. It ambushes from corners, holds in eddies behind pinnacles, and patrols the points where current accelerates and pushes baitfish. Knowing the structure is a significant part of the captain's job.
The Andaman is also a mixed-target environment. A popping session that isn't producing GTs may be producing large bluefin trevally, dogtooth tuna attacking surface lures near the reef edge, Spanish mackerel slashing through the spread, or — on the right tide and the right structure — an occasional wahoo or yellowfin tuna crashing a bait near the surface. The fishery is deep enough in species that unproductive GT days rarely mean unproductive fishing.
The Species and Sizes
The giant trevally (Caranx ignobilis) is the apex target. In Thai Andaman waters, realistic fish run five to twenty-five kilograms for the majority of encounters, with fish in the fifteen to twenty-plus kilogram range being the headline catches that draw serious popping anglers. Larger fish — GTs in the thirty-kilogram range and above — exist and are caught, but they are not the everyday result. Thailand is not the Maldives or certain remote atolls in the Indian Ocean for sheer average GT size, but density and accessibility make the Andaman competitive.
The Similan Islands, being within a national park, carry healthy GT populations that have not been subject to commercial fishing pressure. Fish that live in protected water and have been lightly fished grow older and smarter — meaning some of the GTs on the outer Similan points are seasoned fish that will refuse presentations they've seen before, and experienced GT anglers appreciate this as a proper challenge rather than a limitation.
Where They Live
Similan Islands
The outer west-facing points of the Similan chain — particularly around Koh Bon and Koh Tachai, which sit north of the main Similan group — are renowned for GTs. Koh Bon in particular has a shallow granite plateau that produces strong current during the right tidal phase, concentrating baitfish and the predators that follow them. The GTs that hold on these points are often visible on the surface before you make a cast. They patrol the current edges deliberately and visibly.
The main Similan Islands (numbered 1–9) have productive popping spots along their rocky western faces, particularly on the north and south corners where current runs hardest. The mix here tends toward smaller fish with occasional large surprises.
Surin Islands and Richelieu Rock
Further north, the Surin Islands and the famous dive site of Richelieu Rock — a submerged limestone pinnacle that rises from deep water — sit in genuinely productive GT territory. Richelieu Rock is one of the Andaman's most diverse fishing sites: the structure holds everything from small trevally and mackerel to large amberjack and GTs, and it's a reasonable jigging and popping spot in one location. Access requires park permits and compliance with Surin marine park regulations.
Phang Nga Bay and Outer Reefs
Closer to Phuket, the limestone pillars and reef structures of Phang Nga Bay and the outer reef systems east and southeast of the islands hold GTs in fishable numbers on a year-round basis. These areas are more accessible to day boats and to anglers based in Phuket who don't want to make the overnight run to the Similans. The fish in these areas tend to be smaller on average, but the geography is striking and the fishing is consistently active.
The Technique
Effective GT popping requires understanding the method as much as the gear. Surface lures for GTs — primarily large stickbaits (pencil-style lures worked with a walk-the-dog or erratic twitching retrieve) and poppers (cup-faced lures that produce a distinctive surface disturbance) — need to be worked fast. Not fast relative to bass fishing. Fast in absolute terms: the retrieve that catches GTs is often the one that looks nearly impossible to sustain.
The mechanics of a GT retrieve typically look like this: cast the lure as far as possible toward structure, immediately begin a high-speed retrieve with the rod tip low, and work the lure violently — jerking the rod tip down on each turn of the handle for a stickbait, or pulling sharply to create a surface explosion with a popper. The speed communicates urgency to the fish. A slow or hesitant retrieve on the wrong lure type frequently results in a short strike or no strike at all.
The GT isn't testing the lure. It's trying to kill it before it escapes.
Specific lure selections, sizes, and retrieve variations are covered in the GT popping tackle guide. For the fishery itself, the consistent principles are: fish the current, fish the corners, get the lure in the water before the boat fully stops, and work it like you mean it.
Tide timing is critical. GTs on structure feed most aggressively when the current is running — typically on the hour before and after peak tidal flow. A skilled captain will calculate the tide schedule for each spot and sequence the morning's popping sessions to hit the right windows. Fishing the same spot in slack water produces a fraction of the results.
The Physical Demands
This is important and worth stating plainly: GT popping is physically demanding. The casting weight of large stickbaits and poppers — commonly in the 80–180 gram range — combined with the wind resistance of their large profiles and the repeated, forceful retrieves required across a three-to-five-hour popping session adds up. Anglers who fish the session casually in the first hour and find themselves fatigued by the time the tide peaks have missed the best fishing.
Building up casting fitness before a dedicated GT popping trip is genuinely useful. If you can manage two or three hours of sustained heavy-gear casting at your local club or in training before departure, your effectiveness on the water will be meaningfully better.
Once hooked, a GT in the ten-plus kilogram range on heavy spinning gear is a serious fight. The fish's instinct is to reach structure immediately, and if you're fishing in the right places — near walls, over bommies, in current rips — that structure is often only metres away. The instinct on hookup is to wind and pump immediately, without giving the fish a breath. GTs that reach structure almost always win.
The Boats That Run It
GT popping on the Andaman is run by a mix of operator types. Day boats from Phuket and Khao Lak can reach the outer Phang Nga reef systems and occasionally the southern Similans for focused popping sessions, though the inner Similan parks require permits that not all operators maintain. Liveaboards that run specifically for fishing — rather than dive liveaboards that do fishing on the side — are the best platform for serious GT sessions at Koh Bon, Koh Tachai, and the Surin area. Spending nights aboard and positioning for the morning tide on each spot, rather than rushing to reach a single spot from port, produces better results in this fishery than any day boat itinerary.
The best GT-specific operators carry adequate spare lures — GT popping consumes lures through losses on structure and through the lures simply failing under repeated impacts — and can offer shared gear in the heavy spinning range for anglers who don't travel with their own.
Conservation
GT fishing on the Thai Andaman is almost universally practiced as catch-and-release. The size and strength of GTs makes them poor eating relative to the fishing value they provide as a sport species, and the liveaboard and charter community has broadly adopted a release ethic. Fish fought too long can require revival time; a good captain will know how to revive a GT by moving it through the water until it kicks off. Most fish, handled efficiently, go back quickly.
The national park status over the Similan and Surin areas also carries fishing regulations that operators need to navigate. Confirm that your operator operates within park rules — some areas are no-fishing zones — and that their permit situation is current.
Planning Your Trip
GT popping trips work best when built specifically around the fishery rather than as an add-on to a dive holiday. A three-to-five-day liveaboard with popping as the primary activity, supplemented by jigging during the non-tidal windows, is the most productive format. For tackle specifics and setup recommendations, the GT popping tackle guide covers rod ratings, reel capacity, braid weights, and leader rigging in detail.
For the complete Andaman fishing picture — including how GT popping fits into a mixed-species liveaboard itinerary — read the liveaboard fishing guide. The deep-water jigging guide covers what to do with the hours between peak popping tides. And the Similan Islands fishing guide addresses the park access logistics that any GT-focused trip will need to navigate.
