Segara Anak Lake (2010m) is the crescent-shaped crater lake inside Mount Rinjani, accessible only via a strenuous 3-day trek with descent from the Senaru crater rim. Camping at the lakeshore requires the e-Rinjani permit (350k IDR/day for foreigners), licensed guide, and porters — typically packaged as 5-9M IDR for the full 3-day, 2-night trek. The lake hosts hot springs, trout fishing, and the still-active Mount Baru Jari cone.
# Camping Segara Anak Lake: Inside Rinjani's Crater
Segara Anak ("Child of the Sea") is the crescent-shaped lake at 2010m inside Mount Rinjani's caldera, formed when the original Samalas volcano collapsed in the catastrophic 1257 eruption. Camping at the lakeshore is one of Indonesia's classic mountain experiences — the high-altitude reward at the heart of a 3-4 day trek that ranks among Southeast Asia's best multi-day hikes.
Two trailheads access Segara Anak:
Senaru route (3 days, 2 nights): The shorter approach from the north. Day 1: trek 6-7 hours from Senaru village to Plawangan Senaru crater rim camp (2641m). Day 2: descend 700m steeply into the crater to lake camp (3-4 hours), afternoon at hot springs. Day 3: ascend back to rim, then descend all the way to Senaru (10-12 hours). Doesn't include the summit.
Sembalun-Senaru loop (4 days, 3 nights): The full classic. Day 1: Sembalun trailhead to Plawangan Sembalun camp (2639m, 7 hours). Day 2: pre-dawn summit push to Rinjani peak 3726m, descend back to camp, then traverse to lake camp (long day, 12+ hours). Day 3: rest day at lake, hot springs. Day 4: ascend to Senaru rim and descend to Senaru village.
Most trekkers choose the Sembalun-Senaru loop for the full experience including the summit.
Segara Anak lake is inside Mount Rinjani National Park. Mandatory requirements:
Total package costs (per person, in groups of 2-4):
Cheaper "deals" outside the permit system are illegal and your trek will be cancelled at the rangerÅ check.
The standard lake camp area is on the lake's east shore at roughly 2010m. Facilities are minimal:
Mount Baru Jari (the still-active cone in the lake centre) sometimes vents steam visible from camp.
A 30-minute walk from the main camp, natural geothermal hot springs feed several pools at the lake's south end. Water temperature 35-42C, mineral-rich, beautifully soothing after a cold trek day. Bring swimsuit and quick-dry towel.
The hot springs are the highlight reward of the trek for many. Soak as the sun drops behind the crater rim and the lake turns black.
Segara Anak was stocked with tilapia decades ago and supports a small population. Many porters carry simple fishing line and catch a few fish for the camp dinner. Visitors can join — it's a low-key, low-skill operation. No permit required for line fishing.
The crater hosts:
Lake camp at 2010m gets cold:
Altitude sickness symptoms (headache, nausea, fatigue) hit some trekkers above 2500m on the way up. The lake at 2010m is generally fine but the rim at 2641m can affect sensitive people. Ascend slowly, hydrate aggressively, and descend if symptoms worsen.
The park has strict zero-waste rules at lake camp:
The park rangers do random gear checks at the trailhead — repeat offenders are blacklisted from the park.
The Rinjani Trekking Association runs annual lake cleanups (usually April or November) where volunteers help porters carry out accumulated waste. Trekkers can join via the park office in Senaru.
Segara Anak is sacred to the indigenous Sasak Wetu Telu people, who consider the lake the dwelling of mountain spirits. Annual ceremonies (Pakelem) involve gold offerings cast into the lake. Trekkers may witness ceremonies — observe respectfully from distance.
Use the official e-Rinjani booking portal or a licensed Senaru/Sembalun operator. Reserve 2-4 weeks ahead in peak season (June-August). Off-peak (May, September-October) walk-up bookings often available. The park is closed January-March for monsoon safety; never trek during closure regardless of operator promises.
Standard route: drive from Mataram airport 2.5 hours northeast to Senaru village (the Rinjani trekking gateway). Day 1: trek Senaru trailhead to Plawangan Senaru crater rim camp (2641m, 6-7 hours). Day 2: descend 700m into crater to Segara Anak lake (2010m, 3-4 hours), camp overnight. Day 3: ascend back to rim and descend to Senaru (10-12 hours full day). Sembalun loop alternative is 4 days summit + lake.
Segara Anak lake camp vs Rinjani crater rim camp: rim camp is the 2-day option ending at Plawangan (no descent into crater); lake camp adds 1-2 days and requires the steep crater descent. Lake camp vs Rinjani summit: summit is the 3rd morning's pre-dawn push from Plawangan Sembalun side, separate from the lake. Many trekkers do summit + lake on the 4-day Sembalun-Senaru loop.