Kapas Biru Waterfall, Waterfall in Pronojiwo, East Java, Indonesia.

Kapas Biru is a waterfall in Pronojiwo, East Java, with a drop of about 100 meters over orange rock walls surrounded by dense vegetation and tall bamboo groves. The water collects at the base in a natural pool suitable for swimming.

Kapas Biru opened to the public as a tourist site in 2015, in Dusun Mulyoarjo, Pronojiwo village, Lumajang Regency. The site offers a broad area for pitching tents as well as the waterfall itself. Its water comes from springs on the slopes of Mount Semeru, and the flow is strong, especially in the rainy season.

Locals call it Coban Kapas Biru, using the Javanese word coban for waterfall. The name Kapas Biru, blue cotton, is not explained in the sources; no blue haze or evening optical effect is documented. The site opened to the public in 2015 and is run as a camping and trekking spot by Pronojiwo village, where warungs along the trail sell snacks and fruit from residents' gardens.

From the parking area and ticket booth, the falls are about 1.3 km away on foot, roughly 30 minutes depending on fitness. From Lumajang the site is about 51.6 km; from Malang about 70.1 km, via Turen, Dampit and Ampelgading to Pronojiwo. After Pronojiwo police station, look for the Mulyoarjo mosque and the signposted alley on the right. Warungs along the trail sell snacks and local fruit.

The waterfall drops in two tiers: a lower step of about 90 metres and an upper step of about 10 metres, fed by springs on the slopes of Mount Semeru. The flow swells in the rainy season, when standing directly beneath the fall is dangerous.