As of Jun 19, 2026, 8:54 PM, in season, building toward peak (~July 1). Earth Exhibit tracks the live conditions and flags it the moment it is on.
Each summer, tri-spine horseshoe crabs (Tachypleus tridentatus) come ashore across the intertidal flats of Kasaoka Bay to mate and lay eggs.
Spawning is tightly linked to spring high tides and typically concentrates on a handful of nights from mid-June through August, with local observations concentrated in July and August.
Where to see it
A taste of where to see it. The full map, exact coordinates and the best timing for each spot live in the app.
| Viewing spots |
|---|
| Kasaoka Bay Tri-spine Horseshoe Crab Museum Viewing Platform |
| East Kasaoka Shoreline Tidal Flats (public access) |
| + 1 more spot, with exact coordinates and timing, in the app → |
This is the short version
This page shows a taste. The app has the full list of where to see this, the exact timing, and live conditions for 1,000+ natural phenomena worldwide, so you know the moment one is genuinely worth the trip.