Chōshi tide times

Chōshi sits at the eastern tip of Chiba Prefecture, where the Tone River — Japan's second-longest river — meets the Pacific Ocean at a headland of basalt cliffs. It's one of the major fishing ports in Japan and a significant tide data reference point; the Inubōsaki lighthouse (1874) on the headland is one of the oldest remaining Western-style lighthouses in Japan. Tidal pattern is semidiurnal with a mean spring range of about 1.4 metres. The Kuroshio Current (Japan Current) passes offshore and influences both sea temperature and the local fisheries.

The fishing industry at Chōshi processes enormous volumes of Pacific saury (sanma), mackerel (saba), and sardine (iwashi). The Chōshi fishing harbour is one of the top five landing ports in Japan by volume. Fresh fish from the Chōshi fleet reaches Tsukiji/Toyosu Market in Tokyo within hours of landing. The Uoichiha fish market building and the morning fish auction are accessible to visitors on guided tours — arriving before 5 a.m. to see the auction in full swing is a rare behind-the-scenes experience.

Inubōsaki Cape on the headland north of the harbour has the most dramatic coastal geology near Chōshi — columnar basalt formations, wave-cut platforms, and the lighthouse. At low water, the basalt platforms are accessible by foot for around 30 minutes either side of low tide; rockfish (mebaru), wrasse, and rock bream can be caught from the platform edges. The lighthouse is open for climbing; the view north along the Pacific coast extends to the Kashima coastline on clear days.

Surfers use the beaches south of Chōshi along the Kujūkuri Beach system — a 66-kilometre stretch of exposed Pacific coast that catches Pacific groundswell consistently. The northern section (Chōshi to Iiji) has several reef and beach break sections; the quality varies by sand position and swell direction. Northeast swell from North Pacific storms (October through March) produces the best organised waves along the Kujūkuri stretch.

Chōshi is accessible from Tokyo by train (Chōshi Line from Chiba, about 2.5 hours), making it a feasible day trip for fish market visits or a full weekend for fishing and surfing.

Predictions on this page come from Open-Meteo Marine, a gridded global ocean model. Accuracy is typically within plus or minus 45 minutes on timing and 0.2 to 0.3 metres on height — model-derived, not from a local gauge. For authoritative Japanese tide data, consult the Japan Meteorological Agency at jma.go.jp.