December is Thailand's most complete fishing month. The Andaman Sea is fully open and performing at or near its annual peak. Bangkok has finally shed the last of the monsoon's humidity, and cool mornings make the city's pay-lake circuit more enjoyable than at any other point in the year. Northern reservoirs are in excellent condition, holding fish that have been undisturbed through the wet season and are now feeding heavily as temperatures drop. The one complication December adds is crowds — Christmas and New Year bring a surge of visitors that fills premier venues, top charter boats, and liveaboards to capacity. Plan well ahead or accept reduced options.
The Weather and Water This Month
December sits at the peak of Thailand's cool-dry season. Bangkok daytime temperatures run 28–31°C, with nights dropping to 20–23°C — the coolest the city gets all year. Humidity is as low as the annual cycle permits. The sky is reliably clear and blue. Rainfall is minimal: Bangkok typically receives 20–30mm across the entire month, mostly from brief overnight showers.
Northern Thailand in December is noticeably cooler. Chiang Mai sees daytime highs of 25–28°C and evening temperatures of 12–16°C; at higher elevations and in the hills, nights can reach 8–10°C. A proper fleece or warm layer is not optional for pre-dawn departures on northern rivers or reservoir boats.
The Andaman coast is in its dry-season prime. Seas are calm, northeast trade winds are light and steady, and underwater visibility across Andaman reefs can exceed 25 metres in settled periods. Sunrise is at 6:40 a.m. and usable fishing light extends to around 6 p.m. Charter day trips from Phuket and Khao Lak run twelve-hour days with confidence.
The Gulf of Thailand is mixed. The northeast coast — Koh Samui, Koh Phangan — has generally cleared from November's northeast-monsoon rain by mid-December, though early December can still see wet weather there. Inner Gulf sites around Pattaya and Hua Hin are settled and consistent.
Book December well in advance
Top Andaman sailfish charter boats, premier Bangkok pay-lake pegs, and quality liveaboard cabins can be fully reserved months ahead of Christmas and New Year. December is the one month where showing up without a booking risks genuine disappointment. Make reservations in September or October for peak-period dates.
Freshwater Fishing This Month
Bangkok Pay-Lakes: The Most Pleasant Conditions of the Year
December is the month Bangkok's pay-lake circuit offers the most comfortable fishing conditions of the entire calendar. Cool mornings, low humidity, and the pleasant winter light that arrives with the northeast monsoon make full-day sessions genuinely enjoyable from first cast to last.
Bungsamran Lake is as productive and as busy in December as it gets. Giant Mekong catfish and giant Siamese carp are consistent feeders in the cooler water, and the reduced metabolic demand of slightly lower temperatures actually extends the feeding windows — fish feed more steadily through the day rather than in concentrated bursts. The venue books up on weekends and public holidays; weekday sessions in December are the smart choice if your schedule allows.
IT Lake Monsters draws a full roster of visiting anglers in December, and the arapaima, alligator gar, and giant snakehead fishing is outstanding. The stocked exotic species are not temperature-limited the way some wild freshwater fish are — they feed reliably year-round — and December's comfortable weather means you can put in a proper eight- to ten-hour session without heat-related fatigue.
Palm Tree Lagoon, Exotic Fishing Thailand, Boon Mar Ponds, and Dreamlake Fishing Resort are all worth including in a Bangkok itinerary. Given the holiday crowds, diversifying across venues — rather than committing exclusively to one — gives you more flexibility if a preferred location is booked.
For first-time visitors to Bangkok pay-lakes, the pay-lake etiquette guide and getting to Bungsamran from Bangkok are practical starting points. The fishing with kids in Thailand guide is relevant for families visiting over the Christmas break.
Northern Reservoirs: The Cool-Season Peak
Northern Thailand in December is arguably the most rewarding region to fish in the entire country during this month. The reservoirs and rivers around Chiang Mai, Chiang Rai, and Mae Hong Son are full, clear, and operating at optimal temperature for most species. The cool snaps — nights below 12°C in the hills — concentrate fish near thermally favourable depths and current flows, making location scouting productive.
Mahseer in the northern river systems are in excellent form. December's lower, clearer water means precise presentation matters more than in the monsoon months, but the fish are feeding actively and the rewards for getting it right are substantial. Fly fishing in December's clear conditions calls for more refined mahseer fly patterns — sparse, natural-profile streamers and well-presented nymphs outperform the heavy monsoon-season offerings. Matching local invertebrates when hatches are visible can produce memorable sessions.
Greenfield Valley Resort near Chiang Mai combines managed lake reliability with access to guided river fishing. The resort is a practical base for a mixed trip — two days on the managed lake, two days with a guide on the wild river — and the Chiang Mai area in December is one of the most scenically beautiful times to visit.
Gillhams Fishing Resort in Krabi continues strong through December. The combination of managed lake fishing — giant Siamese carp, chao phraya catfish, mahseer — and the Andaman coast fully operational at its doorstep makes Gillhams one of the most versatile venue choices of the month.
December mornings in Bangkok finally feel like what fishing should feel like — cool enough to hold your coffee without burning your hand, quiet enough to hear the float hit the water.
Saltwater Fishing This Month
Andaman Sea: The Season at Its Peak
The Andaman Sea in December is operating at the height of the year. Conditions are reliably calm, visibility is exceptional, bait schools are concentrated, and the full range of Andaman species are accessible from multiple departure points. The only variable is not weather — it's availability. The top boats are busy.
Sailfish fishing is at or approaching its annual peak. The northern Andaman shelf north of the Similan Islands holds good populations of striped marlin and Indo-Pacific sailfish in December, and charters from Khao Lak are producing multiple-fish days on the right conditions. The sailfish season Thailand guide is the essential reference: it covers the precise grounds, the right techniques, and how to select a charter that fishes ethically and effectively. Marlin fishing Thailand covers the blue-water billfish side of the equation.
GT popping at the Similan Islands and Surin Islands is in full swing. Giant trevally are well-distributed around reef structure, and December's clear water allows poppers to be seen and struck at distance. Experienced GT anglers who can make long casts and maintain a fast, sustained retrieve will be rewarded. The GT popping tackle guide covers equipment selection in detail.
Liveaboard fishing reaches its annual peak in December. Three- to five-night liveaboards out of Phuket and Khao Lak are the most popular format for visiting overseas anglers, combining Similan Islands popping and jigging with blue-water trolling and bottom fishing. December cabins on top liveaboards sell out months in advance — this is not a venue you can book week-of.
Racha Yai and Racha Noi, Koh Rok sailfish grounds, and deep-water jigging on the outer banks are all productive in December and offer alternatives for anglers whose first-choice liveaboard or sailfish charter is unavailable.
Gulf of Thailand
The Gulf mid-month onwards is settled and accessible from Pattaya, Hua Hin, and the inner eastern coast. Barramundi in tidal channels and reef spinning are reliable standbys. By late December, Koh Samui's weather has usually cleared sufficiently for inshore work, though committing to specific dates without flexibility remains a risk. Top Cats Koh Samui is worth checking for Samui-based options.
Recommended Trips
1. Khao Lak Sailfish Peak. A six- to seven-night trip to Khao Lak targeting peak sailfish season. Book by October. The sailfish season Thailand guide has operator information. Avoid the Christmas week itself if you want a relaxed boat — between-holiday slots are better.
2. Similan Islands Liveaboard, December. The definitive Andaman experience. Four to five nights, full GT and jigging program. Book as far in advance as possible for December dates. The liveaboard fishing Thailand guide compares available operators and itineraries.
3. Bangkok Pay-Lakes, Weekday December. Three to four weekday sessions at Bungsamran and IT Lake Monsters. December weekday fishing is the most comfortable and least crowded window for Bangkok's flagship venues. Full-day sessions in cool-season weather are among the most enjoyable experiences the Bangkok circuit offers.
4. Northern Mahseer and Cool-Season Rivers. Four to five days around Chiang Mai targeting mahseer on northern rivers with a specialist guide, combined with managed lake time at Greenfield Valley Resort. Pack a fleece; pack the right flies. One of the best river fishing experiences Thailand offers, in peak condition.
What to Avoid This Month
The Christmas and New Year period — roughly December 22nd through January 2nd — is when popular venues, charter boats, and liveaboards reach absolute capacity. If your travel dates fall in this window and you haven't booked months in advance, adjust expectations accordingly. Costs also spike during this window — accommodation, charters, and venue day fees all carry holiday premiums. Avoid the walk-in approach at any premium Bangkok pay-lake during the Christmas week.
On the Gulf side, avoid committing to early-December Koh Samui offshore trips without robust insurance or full itinerary flexibility; the north-coast wet season can extend into mid-December.
Comfort and Gear Notes
December is the most forgiving month for clothing decisions — cool mornings and warm afternoons mean light layering works throughout. A thin packable jacket for pre-dawn boat departures in the north or on Andaman liveaboard decks is worth carrying. Sun protection clothing remains essential for full-day saltwater sessions regardless of season.
For saltwater December trips, ensure reels are serviced and drag systems are fresh. Bring sufficient GT popping tackle for multiple sessions — poppers and stickbaits take punishment in hard GT strikes and you want backup. If travelling with fishing gear, the flying with fishing tackle Thailand guide covers what to expect at Bangkok and Phuket airports.
The do tourists need a fishing licence in Thailand guide is worth reading before any wild-water fishing trips in December, as national park re-entry and fishing regulations apply to specific areas.
Where to Go Next
December rolls directly into the period many regard as Thailand's finest: January, when the cool-dry season is fully established, Bangkok mornings are at their coolest, and the Andaman sits in glassy near-perfection. Read the January guide to see how the two months compare.
For those who came to December from October's reopening, the full high-season arc runs October through February — December sits at the apex. The best time to fish in Thailand guide provides the annual overview for trip planning across any window.
The key reference pieces for December fishing in Thailand: sailfish season Thailand, liveaboard fishing Thailand, GT popping Andaman, and Bungsamran Lake for Bangkok planning.
