Miyakojima tide times

Yabiji is a 7 km² coral reef platform between Miyakojima and Ikemajima that is submerged for most of the year. During the lowest spring tides — typically a few days in April and May, when spring tide coincides with perigean conditions and the mixed-semidiurnal diurnal inequality maximises the lower-low water — the reef flat drops close to or briefly above the sea surface. On those days, the reef becomes accessible on foot from the Ikema side. Local tour operators on Miyakojima organise Yabiji walking tours timed to the tide prediction; the window is a few hours at most and is weather-dependent. The event is considered one of Okinawa's most unusual natural spectacles. If conditions prevent access in a given year, the next opportunity is roughly 12 months away. Contact local operators in Miyakojima city (Hirara) for current-season tour availability.

Mean tidal range at Miyakojima is approximately 1.2 metres above MLLW in a mixed-semidiurnal pattern. The diurnal inequality in the mixed regime means one of the two daily lows is often significantly lower than the other — and on spring tides this inequality is maximised. The lowest spring low tides of the year (typically April–May) are the window for Yabiji reef exposure. For routine reef snorkelling, checking whether the visit coincides with low water (particularly lower-low) matters for reef flat depth: at high water, the reef crest may have 1.5 metres or more over it; at lower-low, 0.1 to 0.3 metres or less.

Yoshino Beach on Miyakojima's southeast coast has a shallow, accessible fringing reef starting from the beach. The reef begins close to shore and the inner section is shallow enough for beginners at mid-to-high tide. At lower tidal states, the reef flat shallows significantly — fins-only water in places, with the risk of contact with coral if care is not taken. The outer reef slope has deeper water and more advanced dive territory. The coral coverage and fish diversity at Yoshino are high by Japanese standards. Facilities at the beach are minimal — no lifeguard, limited shade. Entry is via a farm road; reef sandals and rash guard or wetsuit are advisable.

The Irabu Bridge connecting Miyakojima to Irabu Island is 3.54 kilometres long — Japan's longest toll-free bridge. Irabu Island and adjacent Shimoji Island (connected to Irabu by two short bridges) have less-visited dive sites, a disused airstrip (Shimoji Airport, formerly used by airlines for training), and quieter beaches than the Miyakojima main island. The channel between the islands produces tidal current that concentrates pelagic fish; boat fishing from Irabu targets bluefin tuna and wahoo in season. The islands are accessible by car from Miyakojima; cycling across the Irabu Bridge is also possible.

No. Predictions here 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. For the Yabiji reef specifically, these margins matter — a 0.2 m error on the predicted lowest low can be the difference between a walkable reef and one that stays submerged. Use JMA's official tide tables at jma.go.jp as the primary source for Yabiji tour planning, in combination with local operator knowledge of recent tide gauge readings. For general planning and orientation, this page is a useful reference tool.