Kosai Surf Fishing Guide: Shirasuka, Okurado and Arai Beach on the Western Enshu-nada

This guide covers the surf in Kosai, Shizuoka, the western end of the prefecture, from the Aichi border to the Imagiri outlet of Lake Hamana. It continues east from the Toyohashi surf as a shallow, sandy beach, with small yellowtail in summer and flounder and yellowtail in autumn and winter. National Route 1 (the Hamana Bypass) runs right behind the beach, so access is easy.

Enshu-nada and the Kosai surf

The Enshu-nada surf runs for more than 100 km from Omaezaki in Shizuoka to the Atsumi Peninsula in Aichi. It faces the open sea and is famous for yellowtail and flounder. In Kosai, the beach is shallow and sandy, and anglers usually wade in waders. The bottom is sand with few snags, so it is beginner-friendly.

Okurado beach has about 5,800 catches logged across all species on the ANGLERS app (as of September 2026), so it is well fished. Here are the spots from west to east.

1. Shiomizaka to Shirasuka beach (“Shiomi Beach”)

Running east from below Shiomizaka on the Aichi border, Shirasuka beach is often called “Shiomi” locally and appears as “Shiomi Beach” on Google Maps. It continues straight on from the Toyohashi surf. The beach is shallow, so wade in waders. It is open sand where distance matters, so a 10 ft surf rod that casts far helps. Small yellowtail are often caught on jig-sabiki rigs in summer, with flounder and yellowtail in autumn and winter.

There is parking, toilets and a convenience store nearby, so it is easy for first-timers. It gets busy with tourists and surfers in summer, so go early.

2. Okurado beach

East of Shirasuka, near the Okurado interchange. A local favourite. There are no obvious inflows or piers, so it is hard to know where to cast at first. A drop-off sits about 30 m out, with roughly 2 m of water. Where waves break white, it is shallower, so watch the breaking waves, and where surfers stand, to read the bottom. There is parking and toilets. Checking catch reports before you go helps.

3. Arai beach (west of Imagiri)

At the eastern end of Kosai, right next to the Imagiri outlet, Arai beach has wave-break blocks and varied current. Imagiri is a channel about 200 m wide linking Lake Hamana to the sea, with constant strong current. On the falling tide, small fish that cannot enter the channel gather around the blocks, drawing flounder, flathead and seabass. Bait anglers catch Japanese whiting; lure anglers target flounder, flathead, seabass and yellowtail. Watch for young yellowtail (wakanago) in summer and big yellowtail (buri) in winter.

The breakwaters and tetrapods at Imagiri are off-limits, so fish from the beach side only. Some reports say the Arai Benten Seaside Park car park (Kosai City Seaside Park car park) is closed for construction, so check the latest parking information before you go. Share the west-facing beach with surfers.

Extra: Arai Sea Fishing Park on rough days

When the surf is too rough, the Arai Sea Fishing Park near Imagiri is an alternative. It is different fishing, but you can catch horse mackerel and more on sabiki rigs, and it is popular with families.

Spot comparison

Fish and seasons

Small yellowtail tend to arrive in summer on the Shizuoka side of the Enshu-nada. In autumn the yellowtail season often starts around Tahara and Irago in Aichi, so checking Aichi catch reports helps you time Kosai.

Safety and etiquette

• Stay out of the Imagiri breakwaters and tetrapods
• Check the latest parking information; never park illegally
• Share the water with surfers
• Always wear a life jacket: rips and sudden drop-offs exist even on shallow beaches
• Check wave and wind forecasts: the open Enshu-nada often has swell
• Take your rubbish home

My take

Kosai sits between the Toyohashi surf to the west and the Hamamatsu surf to the east. It has the shallow sand of the Toyohashi side, plus the big structure of Imagiri at its eastern end. With few obvious features, it tests your ability to read the bottom from the waves and the water colour. Learn to read the beach here, and you can read it anywhere on the Enshu-nada.

Read next

• Hamamatsu Surf Fishing Guide
• Reading Water Clarity on the Surf
• Japanese Yellowtail Surf Season

MINAGIMAN

JAPAN ANGLER

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Born in 1994. Originally from Hyogo Prefecture, I moved to Iwata City in Shizuoka Prefecture in search of the sea. I am an Enshunada surf angler who enjoys surf fishing. I am also active on YouTube, and my fishing grounds range from Irago to Iwata.