Treks and walks · Lachen
Green Lake: the restricted Zemu trek
From Lachen a long trail runs up the Zemu valley toward Green Lake and the north-east face of Kanchenjunga. It needs special permission, a licensed agency and a full crew. We describe it so you can ask the right questions, not as a weekend option.
The Zemu Glacier, one of the largest in the eastern Himalaya, flows from Kanchenjunga toward the Lachen valley. Early climbers approached Kanchenjunga from this side, and the Green Lake area near the glacier gives a view of the mountain's north-east face. The route lies within or near Khangchendzonga National Park, and Siniolchu rises above it.
The trek starts near Lachen and takes roughly 8–12 days return, through forest and then high moraine above 4,000 m. It is a serious expedition-style walk. Indian nationals and foreigners need special permission beyond the normal North Sikkim permit, and only registered agencies can arrange it. Permission has been granted in some seasons and not in others.
If you want to do it, start with registered Gangtok trekking agencies months in advance, budget for guides, porters or pack animals, food and camping gear, and expect a cost many times higher than a shared tour. Since the 2023 flood the approach roads have also been unreliable. Check current status before you travel.
Cost: Special permits and a full trekking crew; ask agents
Questions people ask
Good to know
Can I trek to Green Lake from Lachen?
Only with special permission arranged by a registered agency, in seasons when it is granted. The trek runs up the Zemu valley toward the Zemu Glacier and the north-east face of Kanchenjunga, taking about 8–12 days. It is not covered by the normal North Sikkim tour permit. Check current status before you travel.
How hard is the Green Lake trek?
It is a long, high trek with several days above 4,000 m on moraine and rough ground. You need good fitness, previous high-altitude trekking experience and a full support crew. It is not a trek for beginners, and weather can close the route.
How much does the Green Lake trek cost?
We cannot give a reliable figure, because it depends on permission fees, group size, crew and season, and few agencies run it each year. Expect it to cost many times a standard North Sikkim tour. Ask several registered Gangtok trekking agencies for written quotes.
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