This is Gadeunia Jebbangso Siheung Geobukseom.

Siheung Geobukseom is called "Turtle Island" because, when viewed on a map, it resembles the shape of a turtle. Since it's an island, the West Sea coastline is visible right away, so you can fully enjoy gazing out at the sea.

The cafe has a wide, horizontal layout — not huge like a very large cafe, but it gives a pleasant sense of spaciousness sideways. There's a bakery and brunch available too, so it's nice to enjoy those while watching the sea.

The interior is decorated with a cave-and-sea concept, and the outside view is great, so I enjoyed a cup of coffee in an atmosphere that felt like being inside the sea while looking out at the sea — the vibe was really lovely.