Swordfish in Thailand: An Honest Assessment
There is a version of this article that does not serve you. It would describe swordfish fishing in Thailand with the same confident, detailed authority as a guide to yellowfin tuna or sailfish. It would reference established charter programmes, name specific grounds, and give you the impression that booking a swordfish trip to the Andaman is a straightforward proposition.
That article would be misleading. This one will not be.
Swordfish (Xiphias gladius) — pla dab (ปลาดาบ) — are present in the deep Andaman Sea. Commercial longline vessels operating in Thai waters take swordfish as bycatch. The species is a confirmed, if uncommon, resident of these waters. The deep channels west of the Andaman islands, the underwater ridges and dropoffs of the outer Similan region, and the open deep ocean beyond the continental shelf provide the depth and prey species that swordfish require.
What does not yet exist in Thailand is a reliable, established sport fishery for this species. The targeting of swordfish by recreational operators in Thai waters is at an early, informal stage. A handful of experienced liveaboard captains with access to appropriate grounds have attempted nighttime deepwater drifts with varying results. The species is catchable. It is not predictably, bookably catchable in the way that the rest of the species covered on this site are.
If you are a serious swordfish angler looking for a primary target in the region, Sri Lanka — which has a more developed daytime deep-dropping swordfish fishery — is the honest recommendation. If you are on an extended Andaman liveaboard trip, have the right operator, and the opportunity to attempt a swordfish drift arises as part of a broader itinerary, that is worth pursuing. These are different propositions, and the distinction matters.
The Fish: Xiphias gladius
The swordfish is the sole member of the family Xiphiidae — a lineage separate from the billfishes (marlins, spearfish, sailfish) despite superficial similarities. The rostrum is flat in cross-section rather than round, creating a true blade rather than the rounded spear of a marlin. The body is streamlined and scaleless in adults, the colour a dark purple-blue dorsally fading to pale silver beneath. The caudal fin is deeply crescent-shaped, designed for sustained high-speed cruising rather than the burst-speed acceleration of ambush predators.
Adult swordfish grow to extraordinary sizes — the IGFA record stands at 536 kg, and commercial specimens exceeding 400 kg are documented. In the Andaman, realistic encounter sizes based on commercial longline evidence are in the 40–120 kg range for fish accessible in the depths sport fishing gear can effectively target. This is not a species where you plan around average sizes; the wide variance and inherent uncertainty of deepwater fishing means any swordfish is a significant event.
Swordfish use their rostrum primarily to stun prey rather than to spear it — a distinction from how most anglers instinctively imagine the bill being used. They feed heavily on squid and mid-water fish, and their vertical migration behaviour — deep during the day, shallower at night — is what makes nighttime drifting the preferred technique globally.
Why Swordfish in Thailand is Rare
The rarity of recreational swordfish catches in Thai waters is not primarily a function of swordfish scarcity. It reflects a combination of factors:
Depth requirements: Productive swordfish water in the Andaman begins at around 400 metres and extends to 1,000 metres and beyond. The Andaman Sea does have deep water — the central basin exceeds 3,000 metres — but the transition from continental shelf to deep ocean is not uniformly close to shore. Finding accessible deepwater that is also within practical range of a liveaboard departure point requires careful route planning.
Limited operator experience: Building reliable deepwater swordfish knowledge requires repeated attempts over an extended period, ideally with consistent marks and conditions. In Thailand, where the swordfish fishery is nascent, few operators have made the repeated attempts necessary to build this knowledge base. The result is that most ventures into swordfish territory in Thai waters are effectively exploratory, with no established track record to draw on.
Equipment investment: Deepwater swordfish fishing requires substantial gear investment beyond what most charter boats maintain for general pelagic fishing. Large conventional reels capable of holding 600+ metres of 80 lb braid, purpose-built deepwater rods, appropriate terminal tackle, and a fighting chair or proper standup harness system are needed. The cost and logistics of this specialised setup deter casual attempts.
Commercial bycatch data: The commercial longline industry provides the clearest evidence that swordfish are present in Thai waters. Longline vessels targeting other species — including yellowfin tuna and various billfish — report swordfish bycatch in the outer Andaman. This data point is encouraging for the potential of a targeted sport fishery but does not translate directly to recreational accessibility.
The Technique: Deepwater Nighttime Drifting
Globally, swordfish are targeted through two primary methods: traditional nighttime surface and mid-water drifting, and the more recent development of daytime deep-dropping. In Thai waters, where any targeted attempts have been made, the nighttime drifting approach is what has been used.
The technique involves positioning the boat in deep water (400+ metres) at or after dusk, deploying baits — typically whole large squid on 10/0 to 14/0 circle hooks — at multiple depths using braided line with a weight system to achieve target depth. Light sticks or chemical attractants are attached near the bait to create visible attraction in the dark water column. The boat drifts naturally with the current, covering ground slowly while the baits soak at depth.
Strikes are detected through line movement or rod tip action and may be subtle given the water depth and line belly involved. The fight on a swordfish at 300 to 400 metres of depth is unlike any other offshore encounter — the sheer weight of line and water pressure on the fish creates a sense of fighting something immovable, and fish-management decisions must anticipate the fish's depth changes rather than simply following its surface movements.
"The hard part is not the fishing. The hard part is the waiting. You set your lines at seven in the evening and you might not get a bite until two in the morning, and you might not get a bite at all. You have to be the kind of angler who is comfortable with that uncertainty." — Liveaboard operator with Andaman deepwater experience
Equipment: Not Negotiable
The tackle required for deepwater swordfish is genuinely heavy-duty and represents a significant step up from general pelagic fishing equipment:
Rod: 80–130 lb class standup or unlimited/unlimited roller guide. Length typically 5.5–6 ft. The rod must have the backbone to apply meaningful pressure at great depths where line belly absorbs much of the force.
Reel: Large two-speed lever drag conventional reel — the equivalent of a Penn International 80 VSX or similar. Must hold at minimum 600 metres of 80 lb braid in addition to 400 metres of backing. A reel that runs out of line at depth is a lost fish.
Main line: 80–130 lb braid. Braid is non-negotiable over monofilament for deepwater work — the low stretch is essential for detecting bites at depth and for effective hooksets with circle hooks through hundreds of metres of line.
Leader: 15–20 metres of 200–300 lb monofilament or fluorocarbon, with a short wire section of 10–15 cm at the business end to protect against the bill.
Terminal: 10/0 to 14/0 circle hooks — not J-hooks. Circle hooks are standard for deepwater swordfish globally because of their self-setting tendency, which is important when the angler cannot feel the initial bite clearly. Large split rings connect to swivels; avoid cheap hardware throughout this connection chain.
Weighting system: In-line weights of 500 g to 2 kg, depending on current and target depth. The weight must be attached in a way that can be quickly shed if the fish sounds and takes line rapidly.
This setup is not maintained by most Thai charter boats. If you are seriously pursuing swordfish, confirm equipment availability in advance of departure.
The Honest Swordfish Calculus for Thailand
Here is the straightforward summary of what a swordfish trip in Thailand looks like in practice:
You will need a liveaboard vessel with access to deep Andaman water and an operator willing to attempt a dedicated deepwater drift. You will need to identify an operator who has either made previous attempts or is genuinely experienced in deepwater billfish techniques from other fisheries. You will need the correct equipment, either provided by the operator or brought from home. You will drift in deep water from dusk to the early hours of the morning. You may get a bite. You may not. The chance of a hookup on any given night is impossible to quantify reliably given how few attempts have been made in Thai waters.
This is not a deterrent if the category of fishing — remote, uncertain, demanding, potentially extraordinary — appeals to you. It is a deterrent if you are visiting Thailand for reliable offshore action and swordfish is the primary reason for the trip.
If swordfish is a genuine priority rather than an opportunistic hope, consider Sri Lanka as your regional destination. The daytime deepwater swordfish fishery off the Sri Lankan south coast is more established, with operators who have built genuine knowledge of productive grounds and catch records to support reasonable expectations.
Where to Start
For visiting anglers interested in the possibility of swordfish as part of a broader Andaman liveaboard itinerary, the starting point is direct conversation with operators listed in our liveaboard fishing Thailand guide. Ask specifically:
- Have they, or their crew, previously attempted deepwater swordfish drifts in the Andaman?
- Do they have appropriate deep-water tackle aboard or can they source it?
- Are there grounds within their normal operating area that reach 400+ metres depth?
- What have results looked like on previous attempts?
Honest answers to these questions will quickly separate operators with genuine experience from those offering optimistic speculation. In this specific fishery, the difference matters more than in almost any other.
The swordfish is a remarkable fish, and the idea of connecting with one in the deep Andaman night is compelling. It is worth being ready when the opportunity legitimately presents itself. It is not worth building a trip around a fishery that does not yet reliably exist.
For more on the broader billfish picture in Thai waters, see marlin fishing in Thailand and the Andaman Sea fishing guide.
