Top 10 Lakes of Indonesia 2026

Lake Matano is the deepest lake in Indonesia and the eleventh deepest in the world, reaching 590 metres at its lowest point, a depth so extreme that the bottom of the lake actually sits below sea level, a rare condition known as a cryptodepression. The lake formed in a tectonic graben, a section of crust that dropped between parallel faults, somewhere between one and two million years ago, making it one of the oldest lakes in Southeast Asia. It stretches 28 kilometres long and 8 kilometres wide across a surface area of 164.1 square kilometres, ringed by the forested hills of East Luwu Regency in South Sulawesi. Age and isolation have made Matano a byword among freshwater biologists for endemic life. Roughly a fifth of the lake's diatom species exist nowhere else, and its animal life follows the same pattern: several endemic fish species, freshwater shrimp of the genus Caridina, crabs from the Parathelphusid family and snails of the genus Tylomelania have all evolved in place, in a burst of local diversification researchers have compared to the species swarms of Africa's Rift Valley lakes. The physics of the lake are just as unusual as its biology. Because the surrounding climate stays warm and stable year-round, the water column never fully mixes the way temperate lakes do each winter, leaving a stagnant deep layer that scientists studying early Earth chemistry treat as a working analogue for the anoxic, low-oxygen oceans of the Archean Eon, more than 2.5 billion years ago. Sorowako, on the lake's eastern shore, is the main access point and home to one of Indonesia's largest nickel-processing operations; a passenger ferry crosses between it and the settlement of Nuha. Most visitors combine Matano with a look at neighbouring Lake Towuti, connected by the short Larona River, from hillside viewpoints that take in both lakes at once.

Lake Sentani is Papua's best-known lake, spreading 28 kilometres from east to west and 19 kilometres north to south across the lowlands about 20 kilometres from the provincial capital, Jayapura. Around a hundred square kilometres of water sits ringed by the Cyclops Mountains, and dozens of small islands and inlets break up what would otherwise be a single open sheet of water. The lake's most distinctive human feature is architectural: many Sentani families still live in houses built on posts directly over the water, a tradition documented in the region for well over a century and visible today in villages scattered along the shoreline. Photographs and museum collections from the early twentieth century, including material held by the Netherlands' National Museum of World Cultures, show these pile-dwelling villages and the dugout canoes, or proas, that connect them, alongside men's ceremonial houses raised on the same style of stilts. Isolation has produced its own wildlife here too. The lake is home to fish found nowhere else on Earth, among them the Sentani rainbowfish and red rainbowfish, plus a distinct goby and gudgeon species unique to these waters. Less fortunate is the Sentani sawfish: freshwater sawfish up to three metres long were a well-documented feature of the lake as recently as the 1970s, but they have since disappeared entirely. At the lake's northwest end, the archaeological site of Doyo Lama holds megalithic stones carved with petroglyphs, which some researchers connect to prehistoric contact with Micronesia rather than mainland New Guinea traditions. Growing settlement around the shoreline has also brought a modern problem: untreated household waste draining into the lake has raised coliform bacteria levels in parts of the water. Sentani town, a short drive from Jayapura's airport, remains the easiest base for visiting the lake and its stilt villages by chartered boat.

Lake Singkarak is West Sumatra's second-largest lake after Maninjau, a tectonic basin stretching almost 21 kilometres between the regencies of Tanah Datar and Solok. It sits at 362 metres above sea level, covers 107.8 square kilometres, and reaches a maximum depth of 268 metres, with an average closer to 149 metres, figures that place it among the deeper lakes on this list even though it rarely gets the same attention as its more famous neighbour. The lake's defining creature is ikan bilih (Mystacoleucus padangensis), a small silvery fish found naturally only in Singkarak's waters and long harvested by local fishing communities as both food and income. Ikan bilih has since been introduced to a handful of other Indonesian lakes as a food fish, but Singkarak remains its original home, and dried or fried bilih is sold throughout the surrounding Minangkabau towns as a regional speciality. Much of the lake's natural outflow has been diverted through a tunnel to the Anai River, which runs west to the Indian Ocean near Padang rather than following its old drainage path. The diverted water now powers the Singkarak hydroelectric station, which supplies electricity to both West Sumatra and neighbouring Riau province, making the lake one of Sumatra's working pieces of energy infrastructure as well as a scenic destination. Villages along the eastern and western shores, reachable from Padang by a drive of roughly two hours or from Bukittinggi via the Anai Valley road, offer simple lakeside restaurants that serve bilih fresh from the water, along with grilled fish and rice, making a lap of the shoreline one of the more relaxed half-day trips out of either city.

Lake Poso is Central Sulawesi's largest lake and, at a maximum depth of 450 metres, the third-deepest in Indonesia. It covers 323.2 square kilometres, holds an estimated 21.6 cubic kilometres of water, and sits at 485 metres above sea level inside a tectonic basin shaped by the same fault systems that run through much of central Sulawesi. Like Matano and Towuti to the south, Poso is an ancient lake with a correspondingly rich list of species found only here: eleven endemic fish, including several ricefish, gobies and halfbeaks; eleven endemic species of Caridina shrimp; freshwater snails of the genus Tylomelania; and crabs from three different Parathelphusid genera. That richness is now under serious pressure. Researchers studying the lake describe its endemic species as highly threatened, with some populations possibly already extinct, largely because introduced fish, Mozambique tilapia and common carp among them, have outcompeted and preyed on native species since being introduced for aquaculture. The lake's Indigenous population, the Pamona people, have fished and farmed its shores for generations, and Poso remains central to Pamona cultural identity in Central Sulawesi. Tentena, at the lake's northern tip, is the main gateway town, with guesthouses and one of the region's best-known church buildings overlooking the water; Pendolo anchors the southern shore, and the small village of Bancea, partway along the eastern side, is known locally for an orchid park showcasing wild species collected from the surrounding forest. Reaching Lake Poso typically means flying into Palu, the provincial capital, and driving several hours south to Tentena, or approaching from the south toward Poso town and the Trans-Sulawesi highway network. The lake's clear water has also drawn a small dive and snorkel following, though facilities remain modest compared with Indonesia's more developed lake destinations.

Lake Towuti is the largest lake on the island of Sulawesi by surface area, spreading across 561.1 square kilometres of a tectonic basin in East Luwu Regency, South Sulawesi. It sits at 293 metres above sea level, with an average depth of 120 metres and a maximum of 203 metres, and it holds an estimated 67.33 cubic kilometres of water, smaller by depth than its neighbour Matano, to which it is connected by the short Larona River, but larger in surface area than any other lake in the province. Towuti belongs to the same ancient Malili lake system as Matano and shares its reputation for unusual, highly localised wildlife. Telmatherinid sailfin silversides, small and often brightly finned fish, have diversified here into several forms found nowhere else, alongside endemic gobies and halfbeaks. The lake's most scientifically distinctive resident may be Caridina spongicola, a freshwater shrimp that lives exclusively on freshwater sponges in the lake, one of only two commensal freshwater shrimp species known anywhere in the world. Endemic Tylomelania snails and Parathelphusid crabs round out a food web that has evolved in relative isolation for hundreds of thousands of years. The lake's shoreline is dominated by the mining town of Sorowako, which sits on the strip of land separating Towuti from Lake Matano and serves as the practical base for visiting either lake. From viewpoints in the hills above Sorowako, both lakes are visible at once, laid out in the forested basin like two halves of a single landscape. Because Towuti and Matano sit in a remote part of interior South Sulawesi, most visitors reach the area by a domestic flight to a regional airstrip followed by a road transfer, and facilities remain oriented toward research and mining-industry travel rather than mass tourism, which keeps both lakes quiet even by Indonesian standards.

Segara Anak is the crater lake filling the caldera of Mount Rinjani on Lombok, and at 2,004 metres above sea level it is Indonesia's second-highest caldera lake sitting beside an active volcano. The caldera itself is the scar of one of the most violent eruptions in recorded history: in 1257, the volcano then known as Mount Samalas collapsed in an eruption that ejected an estimated 10 cubic miles of dense-rock-equivalent material, an event some climate researchers link to a documented period of global cooling in the centuries that followed. What remains today is a lake 7.5 by 6.0 kilometres across, covering 11.3 square kilometres and reaching 230 metres at its deepest point. Its name, Segara Anak, means child of the sea in reference to the water's deep blue, ocean-like colour, an image well known enough in Indonesia that the lake appears on the 10,000-rupiah banknote. At the lake's eastern edge, the young volcanic cone of Gunung Barujari rises to 2,376 metres, an active vent that gives the lake its distinctive crescent shape by crowding against one side of the caldera. Because magma still sits close beneath the caldera floor, the lake runs warm for its altitude: recorded temperatures of 20 to 22 degrees Celsius are some five to seven degrees higher than would be expected at 2,000 metres, warm enough for swimming despite the surrounding cold mountain air. The lake was originally fishless, but a stocking programme begun in 1985 introduced tilapia and carp, which bred rapidly and turned Segara Anak into a working fishery as well as a trekking destination; anglers and campers now share its shores with hikers. Reaching the lake requires a multi-day trek within Gunung Rinjani National Park, most commonly via the Sembalun or Senaru trailheads, with an overnight camp on the crater rim before the steep descent to the water, a serious undertaking reserved for prepared, guided hikers rather than a casual day trip.

Lake Tondano is the largest lake in North Sulawesi, sitting at 600 metres above sea level in the highlands about 36 kilometres south of the provincial capital, Manado. It has long served the Minahasa people as both a food source and a transport route, and the lakeside town of Tondano, capital of Minahasa Regency, has grown up around its northern shore. The lake is home to two species found nowhere else: Tondanichthys kottelati, a small halfbeak fish, and Phyllodiaptomus sulawesensis, a species of calanoid copepod first described from Tondano's waters. Both are recorded in the FishBase reference database devoted to global fish biodiversity, which treats Tondano as a distinct evolutionary pocket much like Poso, Matano and Towuti further south, even though it sits in a very different, much shallower kind of basin. That shallowness has become the lake's defining modern problem. Measurements cited in a 2010 Jakarta Post report on the lake's condition found average depth had fallen to around 12 metres, down from roughly 40 metres recorded in 1934, a decline discussed locally in connection with sediment washing in from the surrounding slopes and pressure from fish-cage farming in the shallows. Local and national authorities have since discussed dredging and catchment programmes to slow the trend, a subject that comes up regularly in regional tourism-forum discussions about the lake's future. For now, Tondano remains a working lake rather than a purely scenic one: fish cages dot large sections of the water, and the shoreline road connecting Tondano town to the Bukit Kasih volcanic park nearby gives sweeping views down over the basin. Manado's Sam Ratulangi International Airport puts the lake within an easy day trip of the coast, making it one of the more accessible entries on this list even as its long-term health remains an open question.