The Green Lake trek in Sikkim is walked by only a handful of trekkers a year — a restricted valley in the state's far north, ending at the snout of the Zemu Glacier below the north face of Kanchenjunga, with Siniolchu, once called the most beautiful mountain in the world, filling the valley head. Green Lake is not a trek you simply book; it's an expedition you plan for, and that is exactly its appeal.
This is the wildest itinerary TrekNova runs in Sikkim: eleven days, a maximum altitude of 16,000 ft, and country that the great pre-war Kanchenjunga expeditions walked before you.
What is the Green Lake trek route and itinerary?
The approach is a journey in itself. Day one is the 120 km drive from NJP or Bagdogra to Gangtok for final permit checks and the expedition briefing; day two continues 110 km into North Sikkim past waterfalls and army posts to the old trading village of Lachen at 9,020 ft.
From Lachen the trail leaves the road and enters the Zemu gorge — dense fir and rhododendron with the river thundering below — to the trek base at 10,500 ft. Day four climbs old expedition trails to a wild camp deep in the Zemu valley at 12,800 ft, and day five crosses the treeline over moraine ridges to Green Lake Camp at 15,100 ft, with Siniolchu's fluted ice face suddenly ahead. Day six is a full exploration day to viewpoints at 16,000 ft above Green Lake, facing Kanchenjunga's north wall, the Twins and the great ice river of the Zemu Glacier. The return descends over three days through high camp and the trek base to Lachen, then back via Gangtok to NJP on day eleven.
When is the Green Lake trek open?
The windows are short and strict: April–May and October–November. Spring brings colour to the lower forest zone; autumn brings glass-clear air over the glacier. Outside these months, snow and weather close the upper valley.
How difficult is the Green Lake trek?
Green Lake is rated Difficult at 5/5, but the number understates the character of the trip — this is an expedition, not a trek. There are no teahouses, no crowds and no quick exits: camps are remote, days run five to six hours at altitude, and you sleep high for several consecutive nights. Come with prior high-altitude trek experience, three months of structured training, and the mindset of an expedition member rather than a client.
What does the Green Lake trek cost?
The expedition is priced at ₹34,999 plus 5% GST, against an MRP of ₹44,999. That includes all meals from Gangtok to Gangtok, expedition tents with -20°C sleeping bags, an expedition leader with high-altitude support staff and porters, all permits and liaison formalities, transport between Gangtok and Lachen, and oxygen backup with a comprehensive medical kit and daily health checks. The NJP/Bagdogra–Gangtok cab and extra hotel nights are excluded.
What permits does the Green Lake trek need?
Green Lake lies in a restricted zone, and this is where it differs from every other Sikkim trail: it requires multiple clearances — Army, Forest Department and Home Department — that can only be arranged through registered agencies like TrekNova. Departure dates are confirmed only after permits are issued, so book at least 60 days ahead and keep your travel plans flexible. Indian citizens need a government photo ID; foreign nationals need a Protected Area Permit (PAP) for Sikkim plus additional Home Department clearance.
How to reach the expedition start?
Train to New Jalpaiguri or a flight to Bagdogra, then the five-hour drive up the Teesta to Gangtok, where the expedition formally begins. From Gangtok onwards, transport is on us.
One of the rarest stamps in Indian trekking goes to those who plan early. If the Zemu valley is on your list, start the paperwork now — the Green Lake expedition page on TrekNova has the season's dates.
