Koh Lanta tide times

Spring tidal range at Koh Lanta is approximately 2.5 m. The semidiurnal regime — two highs and two lows per day — means the beach changes character twice daily. At Klong Dao in the north, the difference between high spring (beach width 20–30 m) and low spring (60–80 m of exposed firm sand) is dramatic enough to change how the beach feels. The gentle gradient at Klong Dao makes the exposed tidal flat suitable for walking and jogging at low water. At Long Beach, the low-tide exposure uncovers a rocky shelf below the southern headland with accessible tidal pools. At Kantiang Bay in the south, the horseshoe shape buffers the spring range somewhat, but the tidal sequence is similar. Neap range drops to roughly 0.5–0.8 m and the tidal change is much less noticeable.

Koh Rok (Ko Rok Nai and Ko Rok Nok) is a Marine National Park site 20 km south of Ko Lanta Yai. The coral reef system around both islands is among the healthiest accessible from Ko Lanta. Day trips run November through April; the park closes May through October due to the SW monsoon. The best snorkelling window at the reef is two hours either side of slack water — when the tidal current drops below 0.5 knots, visibility in the reef channels improves significantly as particulate matter settles. Predicted slack times at Ko Rok are approximately 1.0–1.5 hours after the predicted high or low water at Ko Lanta (the propagation delay through the archipelago). Day trips depart Ko Lanta pier at 08:00–08:30; the first snorkel in the water is typically around 10:00, which in the NE monsoon season often aligns with the mid-morning flood-tide slack.

Ko Lanta Old Town (Ban Ko Lanta) is a 19th-century Sino-Portuguese trading village on the NE coast, 6 km north of the main pier. The wooden shophouses are built on stilts over the tidal flat; at low spring the piles are fully exposed and the structure of the historic buildings is visible from the waterfront boardwalk. At high spring the water reaches the boardwalk level and the stilts are submerged. The best photography of the stilted structures is at low tide in morning light. Several of the shophouses operate as guesthouses, cafes, and small museums; the town has a Muslim fishing-village character distinct from the beach resort strip on the west coast. The drive from Klong Dao to Old Town takes 20 minutes on the east-coast road.

November through April is the NE monsoon season and high season on Ko Lanta. The west coast beaches are at their calmest in February and March — trade wind swell has dropped from the December–January peak and the air is dry. November and December are excellent months with reliably clear skies and the first of the season's boat services to Ko Rok and Hin Daeng. May marks the start of the SW monsoon; services to the outer reef sites stop. June through October is the low season — some resorts close, ferry connections to Ko Samui and Phuket are suspended, and the west coast can see 1.0–2.0 m swell on storm days. Kantiang Bay remains the calmest beach on the island through the SW monsoon.

From Krabi Town: minivan and vehicle ferry combination, approximately 2 hours door to the main Ko Lanta pier at Ban Sala Dan. The vehicle ferry crossing at Baan Hua Hin (mainland to Ko Lanta Noi) operates on demand and takes 5 minutes; the second crossing from Ko Lanta Noi to Ko Lanta Yai takes 10 minutes. Both ferry crossings are tide-independent — the channel is deep enough at all stages. From Ao Nang: minivan via Krabi Town, or direct speedboat service (November–April, approximately 1 hour). The speedboat service does not run in the SW monsoon. From Ko Phi Phi: speedboat, 30–45 minutes (November–April only). The vehicle ferry service running from the mainland operates year-round regardless of season, making Ko Lanta accessible even in October.