Mahakam River

Stream Major Borneo river vital for transport and trade

A major river in East Kalimantan (Borneo), the Mahakam supports towns such as Samarinda and Tenggarong. Travelers take longboat cruises to see riverside markets, mangroves and Dayak communities along the waterway.

Main image

The Mahakam River is a major river in East Kalimantan on the island of Borneo, flowing roughly eastward to the Makassar Strait and serving as a regional transport corridor and ecological corridor. It is one of the island’s principal rivers and supports towns, villages and river-based livelihoods along its course.

The river is navigable for long stretches and is used for passenger and cargo boats, connecting inland communities with coastal towns such as Samarinda in the lower basin. Along its lower reaches the river forms a delta and supports mangrove-lined shores, fisheries and riverbank settlements.

Historically and today the Mahakam basin is home to diverse ethnic communities and has been central to regional trade, transport and resource use. The river corridor supports fisheries, small-scale agriculture in the floodplain and growing commercial activities tied to regional markets.

Geographically the Mahakam rises in the central highlands of Borneo and flows east across East Kalimantan to the Makassar Strait; Samarinda is the main city on its lower reaches and functions as the principal access point for river-based travel.

  • Length and role: The Mahakam is one of Borneo's longest rivers, with a total length of roughly 980 kilometres and significant regional economic and transport importance.
  • Best way to visit: River cruises from Samarinda provide one of the most practical ways to experience riverine communities, mangrove habitats and delta landscapes along the Mahakam.

What to See #

  • Upper and middle reaches: Upper and middle reaches, where the river flows through forested and hilly inland Borneo and is used for local river transport and access to inland communities.
  • Lower basin and delta: Samarinda and the lower basin, where the river widens and reaches the Mahakam Delta before discharging into the Makassar Strait near East Kalimantan's coast.
Mahakam River
-0.7951, 117.4631

How to Get to Mahakam River #

The Mahakam River runs through East Kalimantan; the easiest way to reach it is to fly into the regional airports at Samarinda or Balikpapan and then drive to riverside towns. Samarinda sits on the Mahakam and is a common embarkation point for upriver boat services.

From Samarinda and riverside towns such as Tenggarong, local boats and longboats operate along the Mahakam for travel between settlements and upriver destinations.

Tips for Visiting Mahakam River #

  • Use Tenggarong (Kutai Kartanegara) or Samarinda as gateway towns - they are the common launch points for multi‑day river cruises and local longboats (klotoks) on the Mahakam.
  • Plan river travel in the dry season (roughly April-October) when navigation is easier and smaller tributaries are more accessible; rainy-season flows can make rural landings and village visits difficult.
  • Book a local guide or multi‑day klotok cruise to visit upriver Dayak longhouses and remote villages - these trips coordinate logistics, fuel and local permissions that are hard to arrange independently.

Best Time to Visit Mahakam River #

Best visited in the dry season (roughly June-September) when river conditions and travel are most reliable.

Dry season (best for river travel)
June-September · ~24-32°C
Drier weather makes boat travel and riverside access easier and more reliable across East Kalimantan.
Wet season
November-March · ~24-32°C
Heavy tropical rains raise water levels, increase river flow and mosquito activity, and can disrupt travel.
Shoulder months
April-May, October · ~24-32°C
Transitional periods that can be variable - occasional heavy showers but often workable for trips when compared with peak monsoon.

Weather & Climate near Mahakam River #

Climate

Mahakam River's climate is classified as Tropical Rainforest - Tropical Rainforest climate with consistently warm temperatures year-round. Temperatures range from 24°C to 32°C. Heavy rainfall (2081 mm/year), wettest in April.

Air Quality: AQI 65 Moderate
Best Time to Visit
AugustJulySeptember
Temperature & Rainfall
Temperature Range
30°
Warmest Month
25°
Coldest Month
Monthly Conditions

January

January is hot, feeling like 32°C with oppressive humidity. Heavy rain (209 mm) and mostly overcast skies.

55 Acceptable

Comfort

32°
Feels Like Hot
28°C
Temperature
24° 31°
81%
Humidity
Very Humid

Weather

209 mm
Rainfall
1.6 m/s
Wind
Calm
2.0
UV Index
Extreme
12.0h daylight

February

February is hot, feeling like 32°C with oppressive humidity. Significant rainfall (168 mm) and mostly overcast skies.

57 Acceptable

Comfort

32°
Feels Like Hot
28°C
Temperature
24° 32°
81%
Humidity
Very Humid

Weather

168 mm
Rainfall
1.8 m/s
Wind
Calm
2.3
UV Index
Extreme
12.0h daylight

March

March is hot, feeling like 32°C with oppressive humidity. Heavy rain (214 mm) and mostly overcast skies.

57 Acceptable

Comfort

32°
Feels Like Hot
28°C
Temperature
24° 32°
80%
Humidity
Very Humid

Weather

214 mm
Rainfall
1.7 m/s
Wind
Calm
2.3
UV Index
Extreme
12.0h daylight

April

April is hot, feeling like 33°C due to high humidity. The wettest month with heavy rain (222 mm) and mostly overcast skies.

57 Acceptable

Comfort

33°
Feels Like Hot
28°C
Temperature
25° 32°
80%
Humidity
Very Humid

Weather

222 mm
Rainfall
1.6 m/s
Wind
Calm
2.2
UV Index
Extreme
12.0h daylight

May

May is the hottest month, feeling like 33°C with oppressive humidity. Significant rainfall (192 mm) and mostly overcast skies.

59 Acceptable

Comfort

33°
Feels Like Hot
28°C
Temperature
25° 32°
81%
Humidity
Very Humid

Weather

192 mm
Rainfall
1.9 m/s
Wind
Calm
2.0
UV Index
Extreme
12.0h daylight

June

June is hot, feeling like 32°C with oppressive humidity. Significant rainfall (160 mm) and mostly overcast skies.

59 Acceptable

Comfort

32°
Feels Like Hot
28°C
Temperature
24° 32°
81%
Humidity
Very Humid

Weather

160 mm
Rainfall
1.9 m/s
Wind
Calm
1.8
UV Index
Very High
12.0h daylight

July

July is hot, feeling like 32°C with oppressive humidity. Significant rainfall (127 mm) and mostly overcast skies.

61 Good

Comfort

32°
Feels Like Hot
28°C
Temperature
24° 31°
82%
Humidity
Very Humid

Weather

127 mm
Rainfall
2.2 m/s
Wind
Calm
1.9
UV Index
Very High
12.0h daylight

August

August is hot, feeling like 32°C with oppressive humidity. Significant rainfall (129 mm) and partly cloudy skies.

65 Good

Comfort

32°
Feels Like Hot
28°C
Temperature
24° 32°
81%
Humidity
Very Humid

Weather

129 mm
Rainfall
2.4 m/s
Wind
Calm
2.1
UV Index
Extreme
12.0h daylight

September

September is hot, feeling like 33°C with oppressive humidity. Significant rainfall (130 mm) and mostly overcast skies.

61 Good

Comfort

33°
Feels Like Hot
28°C
Temperature
24° 32°
81%
Humidity
Very Humid

Weather

130 mm
Rainfall
2.3 m/s
Wind
Calm
2.2
UV Index
Extreme
12.0h daylight

October

October is hot, feeling like 33°C with oppressive humidity. Significant rainfall (138 mm) and mostly overcast skies.

61 Good

Comfort

33°
Feels Like Hot
28°C
Temperature
25° 32°
80%
Humidity
Very Humid

Weather

138 mm
Rainfall
1.8 m/s
Wind
Calm
2.1
UV Index
Extreme
12.0h daylight

November

November is hot, feeling like 32°C due to high humidity. Significant rainfall (190 mm) and mostly overcast skies.

57 Acceptable

Comfort

33°
Feels Like Hot
28°C
Temperature
25° 32°
80%
Humidity
Very Humid

Weather

190 mm
Rainfall
1.7 m/s
Wind
Calm
2.0
UV Index
Very High
12.0h daylight

December

December is hot, feeling like 32°C with oppressive humidity. Heavy rain (202 mm) and mostly overcast skies.

55 Acceptable

Comfort

32°
Feels Like Hot
28°C
Temperature
24° 32°
80%
Humidity
Very Humid

Weather

202 mm
Rainfall
1.7 m/s
Wind
Calm
2.0
UV Index
Very High
12.0h daylight

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