The main reason Swim through the halocline
Duck-dive two to three metres, feel the temperature change, and look back up at the boats from below.
Destinations · Labuan Cermin
Labuan Cermin, the two-layer mirror lake
Fresh water floats on salt water in Biduk-Biduk, Berau, so clear that wooden boats seem to hover in mid-air. A mainland extension of a Derawan Islands trip.
- Fresh water over salt
- 2 layers
- Boat from the jetty
- ~5 min
- Time at the lake
- 2 – 3 h
- Best season
- Apr – Nov
The lake
A two-layer lake, not a normal freshwater lake
The local name translates roughly as "mirror lake". Fresh water from rain and forest runoff sits on a heavier salt-water layer connected to the sea. The layers do not mix; they meet at a sharp boundary a couple of metres down, and with almost no sediment, light passes through with little scattering.
Float on the surface and you see the sand, sunken timber and fish below with almost no haze. Dive down through the boundary and the water changes temperature and taste within one body-length; look up and the boats above are a clean silhouette.
The lake sits in a narrow basin ringed by limestone and forest, small enough that a wooden boat crosses it in minutes. There is no scuba diving: this is a swimming, freediving and snorkelling site.
At the lake
What you actually do at Labuan Cermin
A short, physical list rather than sightseeing, which is why two to three hours on the water is enough. Freshwater fish also gather over the pale sand near the shoreline.
The main reason 
Deep section Jump into the deep basin
A wooden jumping deck sits over the deep section. Experienced freedivers use the clarity for weightless descents.
Mid-morning Photograph from the boat
With the sun high enough to punch through the surface, the floating-boat effect is at its strongest.
Rinse off sunscreen, insect repellent and soap before entering: the layers are fragile and the local community manages access carefully.
Getting there
On the mainland, on day three of the 4D3N trip
Labuan Cermin is on the mainland in Biduk-Biduk, not on an island. Every trip starts at Kalimarau Airport (BEJ) in Berau, the meeting point for all our Derawan trips.
| Stage | What happens | Approximate time |
|---|---|---|
| Arrival | Kalimarau Airport (BEJ), road to Tanjung Batu, speedboat to Derawan | ~2.5–3 h road, ~40 min boat |
| Day 2 | Island day: Maratua, Kakaban and Sangalaki | By speedboat |
| Day 3 (4D3N) | Early run to the Talisayan whale sharks, Manimbora and Labuan Cermin | ~6 h round trip |
| At the lake | Wooden boat from the Biduk-Biduk jetty to the lake; life jackets at the jetty | ~5 minutes |
Labuan Cermin is part of the 4D3N route.
When to go
April to November, mid-morning
April to November is the best season; December to March is the wetter period, and trips still run. Heavy rain pushes forest runoff into the freshwater layer and reduces clarity for a day or two, so the drier months give the most reliable mirror effect. The same months bring calm island crossings, which is why the whole archipelago shares one best season.
The lake reads best from mid-morning to early afternoon, when the sun drives light straight down. Early morning gives flat water but weaker light; late afternoon brings longer shadows from the ridge.
Best time to visit How to get to Derawan- Jan Rough Reduced
- Feb Rough Reduced
- Mar Variable Mixed
- Apr Calm 20 m+
- May Calm 20 m+
- Jun Calm 20 m+
- Jul Calm 20 m+
- Aug Calm 20 m+
- Sep Calm 20 m+
- Oct Calm 20 m+
- Nov Variable 20 m+
- Dec Rough Reduced
In season Crossings weather-dependent Sea state · visibility
Pairing
Labuan Cermin pairs best with the whale sharks
The whale shark encounter at Talisayan happens at dawn and the lake reads best mid-morning, which is why the two share one early run. On our 4D3N trip that run also stops at Manimbora.
The outer islands (Maratua, Kakaban, Sangalaki) are a boat-based cluster visited together on day two, so the mainland run sits on its own day rather than between island days.
- Talisayan whale sharks: included on 4D3N
- Manimbora: on the same day-three run
- Island days kept together on day two
What the rate covers
Included and not included on the private trip
The private trip begins and ends at Kalimarau Airport. The written inclusion list for your dates comes with the quotation.
Included
- Car Kalimarau Airport ↔ Tanjung Batu
- Private speedboat
- Water cottage or resort stay
- Meals: 6 on 3D2N, 9 on 4D3N
- Snorkel kit: mask, snorkel, life jacket
- Guides and documentation
- Travel insurance and entrance fee
Not included
- Flights to and from Berau (BEJ)
- Fins
- Tips
- Personal expenses
Trip costs
What a Derawan and Labuan Cermin tour costs
Labuan Cermin is part of the 4D3N trip, not a standalone excursion. Published Indonesia Juara rates; the private price depends on the stay.
Rates as published on indonesiajuara.asia. Larger private groups pay less each.
Answers
Labuan Cermin questions
In Biduk-Biduk, in the southern part of Berau Regency, East Kalimantan. It is a mainland site, not one of the Derawan islands. You reach the water by a wooden boat of about five minutes from the village jetty.
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Plan Labuan Cermin
Add the mirror lake to your Derawan trip
Tell us your dates and group size and we will confirm the 4D3N route with Labuan Cermin.