Sandan Falls, Waterfall in Ashibetsu, Hokkaido, Japan

Sandan Falls is a waterfall on the upper Ashibetsu River, a tributary of the Ishikari River, in Okushibetsu, Ashibetsu, Hokkaido. Its main drop is 10 m high and 7 m wide, formed where hard bedrock shifted along a fault to make a stepped riverbed. The river cuts through layered rock in more than ten cascades, of which the main fall is one.

The falls lie near the headwaters of the Ashibetsu River, a tributary of the Ishikari River, about 23 km upstream from where the Ashibetsu meets the Sorachi. After the Ashibetsu Dam was built upstream in 1957, water diversion for hydropower and for the Katsurazawa Dam reduced the flow. Before the war, large numbers of salmon were often seen swimming up the river.

The name Ashibetsu comes from the Ainu word for the river; one reading of ashi means "to stand", said to match the sight of the water rising as the falls are viewed from downstream. The falls are one of Ashibetsu's five noted waterfalls, the Ashibetsu Gotaki, alongside Meoto Falls, Sorachi Great Falls, Nanayo Falls and Hazukizawa Falls.

Sandan Falls lies about 20 km from Ashibetsu city centre, a short walk from National Route 452. A car park for 20 vehicles and toilets are provided, and a promenade leads to an observation deck in a municipal park. The rocks around the falls are closed to entry after past drownings, and bears are often sighted in the surrounding old-growth forest.

Sandan Falls is one of Ashibetsu's five noted falls, the Ashibetsu Gotaki, alongside Meoto Falls, Sorachi Otaki, Nanayo Falls and Hachigatsuzawa Falls. Before the war, large numbers of salmon were often seen swimming upstream here. The surrounding old-growth forest is frequented by bears, so the temporary shop set up in season closes before sunset.