How these days were chosen
Two things make a date good. The tide has to drop below 100 cm so the seabed is exposed — and that has to happen while you're realistically on the island. A four-hour window at 4 am is no use to a day visitor.
So every date below is ranked by walkable minutes between 09:00 and 17:00, not by total window length. Dates marked SPRING fall near a new or full moon, when the tidal range is at its largest — those days also give the highest evening tide, so the gate floats at its most dramatic the same night.
What the numbers mean
- Seabed exposed and walkable below 100 cm
- Gate appears to float above 250 cm
- Typical walkable window 2–4 hours
- Days with any walkable window, next 12 months —
The pick
Ten best dates in the next year
Ranked by walkable time falling between 09:00 and 17:00. Heights are centimetres above chart datum, from Japan Meteorological Agency predictions for Hiroshima. Regenerated daily.
Month by month
The best three days of each month
If your dates are already fixed
Most people can't move a trip around a tide table. If your dates are set, check today's window or the 90-day calendar and plan the day around whatever the sea is doing — the itinerary is built to slide either way.
And if the tide is high the whole time you're there, that isn't a wasted trip. A floating gate is the photograph everyone actually comes for. The walk underneath is the bonus.