Best beaches in Kosai

3 ranked beaches in Kosai, Shizuoka Prefecture

Ranked by the OnlyBeaches Index (OBI) — a 1-10 score blending water purity, conditions, crowd levels and vibe. Updated every 30 minutes.

All beaches in Kosai

1
Arai Beach
Popular sandy beach near prefectural border with easy access
7.0
2
Shirasuka Beach
Quiet sandy shoreline near the western edge of Shizuoka
7.0
3
Washizu Coast Beach
Lesser-known coastal stretch popular with locals
7.0

What makes Kosai's beaches stand out?

Kosai sits in Shizuoka Prefecture, Japan and is home to 3 ranked beaches on OnlyBeaches. Every beach here is scored by the OnlyBeaches Index — a 1-10 metric blending water purity, live conditions (waves, water temperature, wind), crowd intelligence and vibe.

Whether you're after the highest-scoring beach in Kosai or a quieter hidden cove, the list above is refreshed every 30 minutes using live Stormglass and OpenWeather data.