Mount Bosavi

Mount Bosavi is an extinct volcano in Southern Highlands Province of Papua New Guinea that collapsed to form a broad forested caldera. The caldera and its intact montane rainforest are known for high levels of endemic biodiversity and species discoveries.

The caldera supports primary rainforest habitat and has been the focus of biological expeditions and surveys, most prominently a 2009 scientific expedition that documented several species not previously known to science. Researchers and experienced expedition groups visit for biodiversity surveys and remote-area trekking.

Mount Bosavi formed through volcanic activity before becoming inactive and collapsing to create the caldera that exists today. The mountain and its ecosystems have remained relatively undisturbed due to the remoteness of the site and limited access.

The mountain sits inland in the rugged interior of Papua New Guinea’s Southern Highlands Province, reached only by overland travel from local settlements and requiring careful logistical planning for scientific or guided visits.

• Biodiversity discovery: A notable 2009 biological survey documented multiple species new to science, attracting biological research interest.
• Access: Access requires organized expeditions and multi-day treks from nearby settlements; there is no regular tourist infrastructure.

What to See#

• Caldera: A large, forested collapsed volcanic crater that contains intact montane rainforest and steep rim walls, hosting most of the mountain’s endemic wildlife.
• Rim and approaches: Rim and slopes where trails and approaches end, used by scientific teams for access to the interior and wildlife surveys.

There is no commercial transport directly to Mount Bosavi. Typical access begins with a flight to Port Moresby, then onward charter or domestic flight to a regional airstrip (Kiunga, Tabubil or Tari are common staging points) depending on the operator. From the airstrip, travel is by river boat and multi-day trek through rugged jungle. All visits must be arranged with local landowners and an experienced PNG operator; independent attempts are strongly discouraged.

• Arrange an expedition through a well-reviewed PNG operator - independent treks are unsafe and disrespectful to customary landowners.
• Bring a satellite phone or reliable comms - mobile coverage is non-existent once the trek begins.
• Prepare for leeches, deep mud and sudden, heavy rain; gaiters and a waterproof pack cover are essential.
• Ask permission and a guide from the Bosavi clan councils; scientific and tourist access are controlled by local landowners.