RRI.CO.ID, Jakarta - As outdoor enthusiasts increasingly seek immersive nature getaways to unwind on weekends, cave ecotourism is rapidly gaining momentum across the archipelago.

Among the rising stars are Gerongokng Cave in West Kutai (Kutai Barat), East Kalimantan, and Serumi Cave in Biak Numfor, Papua, two distinct natural wonders that offer thrilling river treks and cave-diving experiences.

In Engkuni Pasek Village, Gerongokng Cave has emerged as a major tourist draw. The site features an extensive subterranean river route cutting through massive rock formations. Local officials note that the river trail here offers a longer, more adventurous tubing track than the famed Pindul Cave in Yogyakarta.

“Once inside, visitors are guided slightly uphill, where they encounter a flowing stream known locally as the Idat River,” Acting Head of the Kutai Barat Tourism Agency, FX Sumardi, said on Sunday, July 19, 2026. “The route starts with an entry into the cave before visitors are guided along the river-tracing path.”

Sumardi recommended visiting Gerongokng Cave in the late afternoon around 3 p.m. for optimal natural lighting and cooler temperatures.

Entry tickets are priced at IDR 10,000 (approx. USD 0.56), with nominal additional fees for river-tracing equipment rentals. To support growing visitor numbers, local authorities have fully paved the access roads, reducing travel time from the regency capital to just 25–30 minutes.

Further east in Papua, Biak Numfor Regency holds its own hidden treasure: Serumi Cave, located in Opiaref Village, Oridek Subdistrict. The name Serumi derives from the local Biak language, roughly translating to “is anyone there?” or “a quest.”

The cave’s defining feature is a crystal-clear freshwater reservoir, making it a prime location for cave diving. Because the site remains largely pristine and undiscovered by mainstream crowds, it offers divers an untouched underwater landscape.

“Inside, there is freshwater, which is why it is frequently used for cave diving. The scenery is unique and authentic because it is not yet widely known,” explained Opiaref Village Head Riky Setia Budi Maryen.

Riky advised travelers to plan visits around midday, specifically between 11 a.m. and 12 p.m. local time, when sunlight enters the cavern and illuminates the underwater formations. While local managers provide basic cave-diving gear, visitors are encouraged to bring their own specialized equipment due to limited local inventory.

Admission to Serumi Cave is set at IDR 20,000, excluding vehicle parking fees, offering an accessible gateway to one of Papua’s finest subterranean eco-adventures. (Naura Sofia)