Koh Samui tide times

Predictions: Open-Meteo Marine (MeteoFrance SMOC, 0.08° grid) — heights relative to MSL (not chart datum / LAT). Model-derived.

Model-derived from a global ocean grid. Useful indication; expect about ±45 minutes on average vs. a local harmonic gauge, individual stations vary widely. See /methodology for per-region detail. Not for navigation.

Conditions as of 05:00 local time. Refreshes daily.

Predictions: Open-Meteo Marine (MeteoFrance SMOC, 0.08° grid) — heights relative to MSL (not chart datum / LAT). Model-derived. · Not for navigation.

The angler tradition for major/minor fishing windows: major ≈3-hour windows around moon transit and opposition; minor ≈2-hour windows around moonrise and moonset. Times are Asia/Bangkok local. Folk tradition, not a scientific forecast.

Koh Samui is Thailand's second-largest island, sitting in the upper Gulf of Thailand approximately 35 km east of Surat Thani town on the mainland. The island is roughly circular, 25 km across, with a central highland of tropical forest reaching 635 m at Khao Pom, ringed by a coast that alternates between sandy beach, rocky headland, and working fishing village. The main visitor beaches — Chaweng and Lamai — run down the east coast facing the Gulf. Na Thon on the west coast is the working town and main ferry terminal for services to Surat Thani. The tidal regime at Koh Samui is mixed diurnal. On most days through the second half of the year, the Gulf of Thailand produces one dominant tide cycle per 24 hours: one clear high and one clear low, with a secondary wobble that may or may not register as a distinct event. Near the equinoxes the pattern shifts toward two reasonably equal tidal cycles per day. Spring range runs 2.0 to 2.5 m above Chart Datum; neap range drops to 0.5 to 0.8 m. During neap periods in the Gulf summer, the entire daily tidal swing can fall below 0.5 m — the difference between the highest and lowest point of the day is less than two hand-widths of water. At those neap extremes, the tide is a secondary consideration for nearly any coastal activity. The beach character on the east coast shifts perceptibly through the spring-neap cycle. At high spring water (2.0–2.5 m above CD), Chaweng Beach narrows to 15–25 m of dry sand in the mid-sections. At low spring, the beach widens to 50–70 m, exposing a firm sand flat and scattered coral rubble at the northern and southern ends where the shoreline curves around headlands. The water depth over the inner reef systems at the beach margins drops below 0.5 m at low spring, making the snorkelling uncomfortable but exposing reef structure for observation. Snorkelling at Koh Tan, the small island 5 km south of Samui's Taling Ngam beach on the west coast, works best on the incoming tide or at high water, when the reef flat on Koh Tan's north side has 1.0–1.5 m of clear water overhead. At low spring the flat sits under 0.3 m; fins drag on coral. The Big Buddha temple (Wat Phra Yai) stands on a small island connected by a causeway at Bangrak on the NE coast. The causeway is accessible at all tidal stages, but the mudflat and mangrove fringe around the causeway base expose significantly at low spring. The NE monsoon season runs November through January; Chaweng and Lamai face the exposure direction and can receive wind-generated swell of 0.5–1.5 m on persistent northeast winds. Photographs of Chaweng with clear blue water typically require calm periods outside peak NE season or early-morning light before the sea breeze builds. Shore fishing from the northern headland at Hat Bophut and from the rocky outcrops at Lamai's two granite boulders (Hin Ta and Hin Yai) is most productive on the run-in tide — the incoming water activates feeding behaviour and the increasing depth holds fish closer to the headland structure. The ferry terminal at Na Thon pier handles standard tidal variation without adjustment; the pier is built to accommodate the full spring range. Samui's interior is accessible via the ring road; the 50 km circuit takes 90 minutes by motorbike and passes coconut plantations, viewpoints over the Gulf, and the fishing village of Bang Po on the north coast where outrigger boats work the mixed diurnal tidal current for mackerel and snapper on the flood. The predictions on this page come from Open-Meteo Marine, a gridded global ocean model; accuracy is typically within ±45 minutes on timing and ±0.2–0.3 m on height. For activity-critical timing in Thai waters, cross-reference with Thai Meteorological Department (TMD) official tide tables.