Lake Akan

Lake Caldera lake in Hokkaido noted for marimo algae

Lake Akan in Hokkaido sits inside Akan National Park; tourists come for boat rides to see marimo moss balls, lakeside onsen towns, Ainu cultural centers and nearby hiking.

Main image
1 Chome Akanchō Akankoonsen, Kushiro-shi, Hokkaidō 085-0467, Japan - panoramio.jpg
Akanko Lake - panoramio.jpg
IMG 0729CAkan Lake.JPG
Kushiro, Hokkaido Prefecture, Japan - panoramio (1).jpg
Kushiro, Hokkaido Prefecture, Japan - panoramio.jpg
Lake Akan - Hokkaido - 2021 12 09 - various 17 11 55 494000.jpeg
Lake Akan - Hokkaido - 2021 12 09 - various 17 12 26 277000.jpeg
Lake Akan - Hokkaido - 2021 12 09 - various 17 13 00 397000.jpeg
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Lake Akan is a caldera lake in Akan National Park on the island of Hokkaido, Japan. It is best known for its marimo, the rare spherical green algae that occur naturally in the lake and nearby waters.

The lake is a regional recreational centre with boat cruises, shoreline walking routes and hot-spring resorts on its shores. Visitors come for marimo observation, short cruises across the water and to use nearby onsen facilities that serve as bases for lake access.

The lake occupies a volcanic basin formed by eruptions and lava flows from surrounding volcanoes; its present shoreline and islands are the result of that volcanic activity. Protection measures focused on the marimo colonies and surrounding parkland have been in place for decades.

Lake Akan lies in eastern Hokkaido within Akan National Park, on the interior of the island rather than the coast. The nearest larger urban centres in eastern Hokkaido serve as access points for visitors to the park.

  • Marimo colonies: Home to one of the few natural populations of marimo, the rare spherical colonies of Aegagropila algae that are protected as a natural monument in Japan.
  • Access and seasons: Accessible year-round with seasonal highlights in autumn foliage and winter ice - boat services and short cruises operate in the warmer months.

What to See #

  • Akanko Onsen: Onsen town on the lake shore that serves as the main gateway for cruises, marimo viewing and boat excursions.
  • Marimo exhibition centre: Small exhibition and observation facilities that explain and display the lake's marimo colonies and local ecology.
Lake Akan
43.4535, 144.1022

How to Get to Lake Akan #

From Kushiro Station you can reach Lake Akan (Akan-ko) by highway bus operated toward Akanko Onsen; the ride takes about 1.5-2 hours. By car it’s roughly an 80 km drive from Kushiro along National Route 240 and local roads (about 1.5 hours); there is short walking access from the Akanko Onsen bus stop or parking area to the lake shore (a few minutes).

Tips for Visiting Lake Akan #

  • Head to the Akan-ko (Akan Onsen) area and visit the Marimo Exhibition and Research Center - short sightseeing boat cruises from the Akan-ko pier are the most reliable way to see marimo colonies close up.
  • To avoid day-trip tour crowds, aim for the first boat in the morning or later afternoon; the onsen town around the lake is the main arrival point for buses and gets busiest in mid-day.
  • Autumn is a popular time for foliage around Lake Akan (peak typically in October), so expect more visitors then and book any boat tours and accommodation in advance.

Best Time to Visit Lake Akan #

Best from late spring through early autumn (May-October) for mild weather, easy access and scenic views.

Summer
Jun-Aug · 15-25°C
Warmest, snow-free period ideal for hiking, boat trips and enjoying nearby onsen and marimo viewing.
Autumn
Sep-Nov · 5-15°C
Clearer skies and spectacular fall foliage (especially October) around the lake.
Winter
Dec-Mar · -10-0°C
Cold with heavy snow; the lake and surrounding roads are often frozen and snowy.

Weather & Climate near Lake Akan #

Climate

Lake Akan's climate is classified as Warm-Summer Continental - Warm-Summer Continental climate with mild summers (peaking in August) and freezing winters (coldest in January). Temperatures range from -15°C to 22°C. Abundant rainfall (1248 mm/year), wettest in September.

Best Time to Visit
AugustJuneJuly
Temperature & Rainfall
Temperature Range
34°
Warmest Month
-27°
Coldest Month
Monthly Conditions

January

January is the coldest month with highs of -6°C and lows of -15°C. Moderate rainfall (71 mm) and partly cloudy skies.

34 Poor

Comfort

-11°
Feels Like Freezing
-11°C
Temperature
-15° -6°
95%
Humidity
Very Humid

Weather

71 mm
Rainfall
2.6 m/s
Wind
Calm
0.1
UV Index
Low
9.2h daylight

February

February is freezing with highs of -6°C and lows of -15°C. Moderate rainfall (58 mm) and partly cloudy skies.

36 Poor

Comfort

-11°
Feels Like Freezing
-11°C
Temperature
-15° -6°
94%
Humidity
Very Humid

Weather

58 mm
Rainfall
2.7 m/s
Wind
Calm
0.3
UV Index
Low
10.3h daylight

March

March is freezing with highs of -2°C and lows of -10°C. Significant rainfall (107 mm) and mostly overcast skies.

31 Poor

Comfort

-6°
Feels Like Freezing
-6°C
Temperature
-10° -2°
88%
Humidity
Very Humid

Weather

107 mm
Rainfall
3.3 m/s
Wind
Light Breeze
0.5
UV Index
Moderate
11.8h daylight

April

April is cold with highs of 6°C and lows of 0°C. Regular rainfall (88 mm) and mostly overcast skies.

42 Poor

Comfort

Feels Like Cold
C
Temperature
81%
Humidity
Very Humid

Weather

88 mm
Rainfall
3.7 m/s
Wind
Light Breeze
0.9
UV Index
Moderate
13.3h daylight

May

May is cold with highs of 12°C and lows of 5°C. Significant rainfall (104 mm) and mostly overcast skies.

50 Acceptable

Comfort

Feels Like Cold
C
Temperature
12°
82%
Humidity
Very Humid

Weather

104 mm
Rainfall
3.5 m/s
Wind
Light Breeze
1.2
UV Index
High
14.5h daylight

June

June is cool with highs of 16°C and lows of 10°C. Regular rainfall (86 mm) and mostly overcast skies.

61 Good

Comfort

13°
Feels Like Cool
13°C
Temperature
10° 17°
84%
Humidity
Very Humid

Weather

86 mm
Rainfall
2.9 m/s
Wind
Calm
1.3
UV Index
High
15.2h daylight

July

July is mild with highs of 21°C and lows of 15°C. Regular rainfall (96 mm) and mostly overcast skies.

61 Good

Comfort

18°
Feels Like Mild
18°C
Temperature
15° 21°
86%
Humidity
Very Humid

Weather

96 mm
Rainfall
2.5 m/s
Wind
Calm
1.4
UV Index
High
14.9h daylight

August

August is the warmest month with highs of 22°C and lows of 16°C. Significant rainfall (141 mm) and mostly overcast skies.

67 Good

Comfort

19°
Feels Like Mild
19°C
Temperature
16° 22°
85%
Humidity
Very Humid

Weather

141 mm
Rainfall
2.5 m/s
Wind
Calm
1.3
UV Index
High
13.8h daylight

September

September is cool with highs of 18°C and lows of 11°C. The wettest month with heavy rain (173 mm) and mostly overcast skies.

55 Acceptable

Comfort

15°
Feels Like Cool
15°C
Temperature
11° 18°
84%
Humidity
Very Humid

Weather

173 mm
Rainfall
2.6 m/s
Wind
Calm
0.9
UV Index
Moderate
12.4h daylight

October

October is cold with highs of 12°C and lows of 5°C. Significant rainfall (136 mm) and partly cloudy skies.

52 Acceptable

Comfort

Feels Like Cold
C
Temperature
12°
84%
Humidity
Very Humid

Weather

136 mm
Rainfall
3.0 m/s
Wind
Light Breeze
0.5
UV Index
Moderate
10.9h daylight

November

November is cold with highs of 6°C and lows of -2°C. Significant rainfall (115 mm) and partly cloudy skies.

44 Poor

Comfort

Feels Like Cold
C
Temperature
-2°
85%
Humidity
Very Humid

Weather

115 mm
Rainfall
3.0 m/s
Wind
Light Breeze
0.2
UV Index
Low
9.5h daylight

December

December is freezing with highs of -1°C and lows of -9°C. Moderate rainfall (73 mm) and partly cloudy skies.

38 Poor

Comfort

-5°
Feels Like Freezing
-5°C
Temperature
-9° -1°
91%
Humidity
Very Humid

Weather

73 mm
Rainfall
2.6 m/s
Wind
Calm
0.1
UV Index
Low
8.8h daylight

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