Gulf of Thailand — July 2026 Fishing Report
While the Andaman coast sits out the monsoon and the rest of the fishing world watches the weather, the Gulf of Thailand quietly gets on with being excellent. July is peak GT season on the northern Gulf coast. Longtail tuna school in the deep water off Chumphon in numbers that visiting anglers find hard to believe until they see it. The Spanish mackerel action between Ban Krut and the Koh Tao seamounts is about as reliable as pelagic fishing gets. And in the southern Gulf, the offshore pinnacles around Koh Tao deliver yellowfin, dogtooth, and the occasional wahoo to anglers who make the effort to jig them properly. July is not a fallback month for the Gulf — it is a genuine highlight.
Water and Weather
The Gulf coast from Cha-Am to Chumphon receives 120–160mm of rainfall in July, significantly less than the Andaman. Rain arrives in afternoon squall patterns — sharp, intense, and typically short. Morning conditions are usually the best of the day: light winds from the southwest, seas of 0.5–1.0 metre in the northern Gulf, calm to slight in sheltered bays. The sea breeze builds from around 11 am, with typical afternoon seas of 1.0–1.5 metres. These are excellent charter-fishing conditions.
Sea surface temperatures across the Gulf run 29–31°C — warm, productive water for pelagic species. Visibility at most offshore grounds is 8–15 metres. Baitfish schools are highly visible throughout the water column during July, and the pelagic species that key on them are easy to locate with basic electronics. Current patterns set up well-defined upwelling zones around the seamounts south of Koh Tao, making June and July the best months for deep jigging at these locations.
What's Biting Now
Giant trevally (GT) — The GT season is fully established by July and at its statistical peak. Inshore schools patrol the rocky headlands between Hua Hin and Prachuap Khiri Khan, with the Khao Takiab headland and the rocky points south of Prachuap producing consistent shore GT encounters. Offshore, the Chumphon Pinnacle area holds individual fish over 30kg. PE8–10 setups with 150g+ metal jigs and surface iron poppers are appropriate for the offshore pinnacle fish.
Longtail tuna — The Gulf's most reliably abundant pelagic in July. Fish school in the 3–8kg range throughout the main fishing grounds between Ban Krut and the offshore structure south of Koh Tao. High-speed trolling with feathers covers ground efficiently; slow-trolled skirted lures account for individual larger fish up to 12kg. Jigging with medium-weight stainless jigs in the 80–150g range through visible bait schools is the most exciting approach and produces consistent results from the charter boats operating out of Chumphon.
Spanish mackerel (narrow-barred) — Active and plentiful throughout the northern Gulf offshore grounds. A fish to 50kg is possible; most catches run 5–20kg. Trolling is the standard approach — chrome lures and konahead skirted lures at 7–9 knots. The stretch of water between Ban Krut and the Koh Tao approaches produces reliable Spanish mackerel through July.
Yellowfin tuna — The southern Gulf's primary July jigging target. Koh Tao's Chumphon Pinnacle and Southwest Pinnacle rise from significant depths and concentrate yellowfin in the 10–35kg range. Heavy jigging tackle with 300–500g metal jigs worked at depth produces these fish for experienced jigging anglers. A small number of specialist overnight charters from Koh Samui target this fishery.
Cobia — Encounters increase in July as cobia associate with any floating structure — including whale sharks occasionally present in July Gulf waters. Cobia are opportunistic feeders and take live baitfish, large soft plastics, and heavy jigs. A 15–30kg fish is a realistic result. The Sichang Island area in the northern Gulf produces cobia reliably for the charter boats that specifically target them.
Squid (loligo species) — July is an excellent month for squid jigging in the northern Gulf, particularly in the shallow grounds around Hua Hin and Pattaya. Night squid trips produce excellent numbers and the fresh squid are invaluable as bait for the following morning's fishing. Several charter operators at Pattaya run dedicated squid jigging nights through July and August.
Grouper (various) — The reef and rocky-bottom grounds throughout the Gulf hold grouper year-round. July produces consistent catches of coral grouper, flowery grouper, and the occasional large queensland grouper around the reef structures between Koh Samui and Koh Tao. Bottom rigs with fresh squid and mackerel fished at anchor produce grouper throughout the day.
What to Target This Month
Top pick: longtail tuna and Spanish mackerel from a Chumphon day charter. Chumphon's charter fleet operates full schedules in July and the pelagic fishing grounds accessible within a 45-minute run from the harbour are genuinely world-class in this period. A 10-hour day charter with an experienced skipper who fishes these grounds daily is the most reliable way to access the best action. Expect to run 20–30km offshore to find the current lines where baitfish schools and their pursuers concentrate.
Second pick: GT on the rocks south of Prachuap Khiri Khan. The southern section of Prachuap Bay and the headlands below town hold GT schools throughout July. Shore fishing here requires commitment — 4 am alarm calls, appropriate footwear, and PE6–8 tackle — but the fish are genuinely present and the scenery around this undervisited part of the coast is remarkable. Accommodation in Prachuap Khiri Khan town is excellent value and the seafood is outstanding.
Third pick: Koh Tao jigging for yellowfin. A overnight ferry from Chumphon or a speedboat from Koh Samui lands you on an island with excellent accommodation, clean water, and specific jigging access to some of the Gulf's deepest pinnacle structure. Book a half-day jigging charter through a reputable operator on Koh Tao — several dive shops run dedicated jigging trips. Bring your own PE4–6 jigging outfit if you have one, but quality tackle hire is available.
What to Avoid
The southern Gulf can develop significant sea states if a tropical depression moves through the South China Sea or Gulf — a low-probability but real July risk. Monitor Marine Department forecasts and have a contingency plan if your charter is scheduled for a day that a system develops. Avoid overly optimistic claims from charter operators about fishing in rough conditions — the Gulf is comfortable in normal July weather but can be unpleasant in 2-metre seas. The shallow-water grounds inside Pattaya Bay fish well but are crowded in July weekends — book ahead or fish midweek.
Chumphon Charter Booking
Chumphon is consistently underrated as a Gulf fishing destination despite being one of the most productive pelagic grounds on the Thai coast. July charter bookings fill on weekends — if you're planning a trip specifically targeting the longtail and Spanish mackerel action off Chumphon in July, contact operators at least two weeks in advance. The charter boats operating out of Tha Yang Pier are the main fleet; ask at the Chumphon town fishing tackle shops for current operator recommendations.
Venue Spotlight
Chumphon Offshore Grounds (Chumphon Province) — The offshore grounds between Chumphon town and the deep-water banks 20–35km from shore are the Gulf's most productive inshore pelagic fishery in July. The Chumphon Canyon and associated current breaks concentrate baitfish and the pelagic species that key on them in numbers that few other Gulf locations match. The town has a modest but functional charter fleet and accommodation is inexpensive and plentiful. Fly into Chumphon Airport from Bangkok (45 minutes) or drive the 460km via Highway 4.
Khao Takiab and Hua Hin Rocky Shore (Prachuap Khiri Khan Province) — The distinctive quartzite and granite headlands south of Hua Hin are the most accessible shore GT addresses on the northern Gulf coast. Khao Takiab, the large rocky hill jutting into the sea just south of Hua Hin town, provides genuine current concentration and holds GT, Spanish mackerel, and shark mackerel at various tidal phases through July. Fishing from the road-accessible platforms at the base of the hill requires no boat and no guide.
Koh Tao Pinnacles (Surat Thani Province) — Accessible by ferry from Chumphon (2 hours) or Koh Samui (45 minutes by speedboat), Koh Tao is a low-key island with high-quality jigging in deep water immediately offshore. The Chumphon Pinnacle rises from 36 metres to within 14 metres of the surface and concentrates large pelagics and grouper throughout July. The Southwest Pinnacle drops to 70 metres and is the preferred address for the larger yellowfin and dogtooth.
Logistics in July
The Gulf coast accommodation — Hua Hin, Prachuap Khiri Khan, Chumphon, and Koh Tao — is in low-to-mid season in July, meaning good availability and rates below peak. Koh Tao in particular is significantly cheaper in July than December through March. Ferry services to Koh Tao from Chumphon run twice daily and are reliable in the Gulf's typically calm July conditions. Driving down Highway 4 from Bangkok to Hua Hin takes 2.5–3 hours and to Chumphon around 7 hours; overnight trains from Bangkok's Hua Lamphong Station are a comfortable alternative.
Charter bookings at Hua Hin, Pattaya, and Chumphon are best made through WhatsApp contacts direct with skipper — the fishing community operates informally but reliably. Ask in Thai angling groups on Facebook for current operator recommendations specific to July.
Looking Ahead to August
August mirrors July on the Gulf — reliably good pelagic conditions, active GT schools, and productive jigging over the southern pinnacles. One additional element appears in August: the probability of a tropical storm or typhoon in the South China Sea or Gulf is slightly elevated, which can occasionally deliver disrupted charter schedules for 3–5 days before conditions normalise. August is not a month to avoid on the Gulf, but it is a month to maintain flexibility in your itinerary around weather windows.
