RRI.CO.ID, Samarinda - A rare geological marvel hidden within the belly of Maratua Island is capturing the attention of the global travel community, as the pristine brackish lake of Gumantung Cave emerges as East Kalimantan’s latest premier ecotourism highlight.

Located within the scenic Teluk Alulu area, Gumantung Cave presents an extraordinary subterranean landscape. Inside the massive cavernous network, visitors are met with a crystal-clear, turquoise brackish lake that contrasts dramatically with towering karst formations, intricate stalactites, and stalagmites.

The site offers a highly distinct travel experience, allowing adventurers to navigate the ultra-calm waters using small kayaks. To reach this hidden oasis, travelers complete a brief overland trip from Maratua’s main jetty followed by a light, immersive trek along a well-preserved jungle footpath.

The location has quickly earned a reputation among ecotourists as a therapeutic, silent space perfectly suited for ecological relaxation.

The East Kalimantan provincial administration has warmly welcomed the growing interest in the site, framing it as a benchmark for responsible, high-value tourism development. Speaking in Samarinda on Sunday, July 19, 2026, Head of East Kalimantan Tourism Agency Muhammad Faisal emphasized the administration's strategic vision for the cave's long-term preservation.

"This destination offers a rare geological phenomenon, where visitors can find a clear, turquoise brackish lake hidden right inside the belly of the cave. The vast cavernous space allows tourists to immediately paddle around the calm brackish waters using small kayaks. This is a highly unique ecological relaxation experience rarely found on other tropical islands," Faisal said.

He explained that because the karst hydrology and surrounding forest ecosystems are highly delicate, the administration has imposed a strict environmental safeguard, capping visitation at a maximum of 70 people per day.

According to the tourism chief, this regulatory limit is crucial to fostering collective environmental awareness among travelers. The administration aims to prove that premium, low-impact tourism can effectively boost the creative economy and support coastal communities on Maratua Island without compromising the island's vital natural infrastructure. ***