What the survey found
The main spring (J1) measured 64.9°C and a smaller one 10 m upstream (J2) about 64°C. In the lab both waters were slightly alkaline, pH 8.5 to 8.6, and high in sulphate (about 790 to 900 ppm), calcium and sodium, with very little magnesium.
Geologists read this as acid sulphate water from a distant source that was neutralised by cold groundwater before surfacing. The 1991 paper estimated the springs lose about 15 MW of heat into Sungai Jepun, which was flowing at around 2,000 litres a second.
How it fits with the Tawau springs
The Tawau-area springs at Apas Kiri, Sungai Balung and Tawau Hills Park ring the Maria volcanic complex. Sungai Jepun lies well east of that group; the 1991 survey placed it outside the Tawau area, though GeoSM's 2021 summary lists it with Sabah's volcanic springs.
Visiting
We don't know who owns the land, whether there is a track, or whether the springs still flow as they did in 1989. The springs drain into Sungai Jepun: the 1991 paper measured the river at about 30°C upstream of them and 32°C downstream.
Getting there
No route has been published. The 1991 Geological Survey location map places the springs on Sungai Jepun just north of Gunung Pock, in Semporna district between Tawau and Semporna town. The map pin is approximate, read from that small-scale map, and could be a kilometre or two out.
Before you go
- Don't set out on the map pin alone; it is read off a small-scale 1991 survey map.
- Ask around Semporna for someone who knows Sungai Jepun before trying to find it.
- At about 64°C the spring outlets can scald. The river beside them was only about 30 to 32°C in 1989.
- For a developed hot spring in the region, Tawau Hot Springs has built pools, though recent reviews say it is run-down.
Questions people ask
Where are Sungai Jepun Hot Springs?
On Sungai Jepun just north of Gunung Pock, in Semporna district, according to the 1991 Geological Survey map. The exact spot is not published.
How hot are Sungai Jepun Hot Springs?
The 1989 survey measured 64.9°C at the main spring and about 64°C at a second outlet 10 m upstream.
Are Sungai Jepun Hot Springs open to visitors?
Unknown. There are no facilities, no published access and no recent visitor reports.
What kind of water comes from Sungai Jepun Hot Springs?
Slightly alkaline (pH 8.5 to 8.6 in the lab) and high in sulphate, at about 790 to 900 ppm, with almost no magnesium. Geologists read it as acid sulphate water neutralised by cold groundwater before it surfaced.
Other springs within 150 km
Sources
Facts on this page were checked against these sources. Prices and hours change; confirm with the operator before a long drive.
- Lim Peng Siong, Francis Intang & Chan Fook On (1991), Geothermal prospecting in the Semporna Peninsula with emphasis on the Tawau area, Geological Society of Malaysia Bulletin 29, pp. 135–155
- Chong, Mohd. Noh & Liew (2000), Hot springs at Tawau Hills Park, Sabah, Malaysia (cites Sahat et al. 1989, Preliminary survey of the Sungai Jepun hot spring)
- GeoSM Malaysia: Air panas volkanik di Sabah (2021)
- OpenStreetMap: Gunung Pock, Semporna
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