Oido & the Siheung Tidal Flats

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A red hourglass-shaped lighthouse at the end of a causeway, with vast tidal flats and clam beds behind it.

Oido was once a real island; land reclamation joined it to the mainland and turned it into a standard day trip for the capital region. The causeway runs straight out to sea, and at its end stands the red hourglass lighthouse that has become the local emblem. At low tide the mudflat runs to the horizon and people wade out to rake for clams; at high tide the water slaps just under the railing. Grilled seafood restaurants line the shore, and the sun sets straight into the Yellow Sea — something Korea's east coast cannot offer.

Visitor information

When is the best time to visit Oido & the Siheung Tidal Flats?

April–June and September–October

How long do you need at Oido & the Siheung Tidal Flats?

2–3 hours

What are the opening hours of Oido & the Siheung Tidal Flats?

All day

Did you know

Formerly an island, joined to the mainland by reclamation projects.
The hourglass-shaped Oido lighthouse is about 30m tall and has a viewing deck.
The Siheung flats are part of the extensive west coast tidal system.
Prehistoric shell middens have been excavated in the area.

Travel tips

Check the tide table: low water for the flats, high water for lighthouse photos.
Take the Suin-Bundang line to Oido station, then a bus to the shore.
At weekends the seafood restaurants fill up from the afternoon.

Source: https://english.visitkorea.or.kr/

Updated: 2026-08-05