Green Lake Trek
Mangan (North Sikkim), Sikkim
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- Max altitude
- 4,935 m
- Days
- 13 days
- Distance
- 88 km
- Difficulty
- Challenging
A remote, fully self-supported expedition-style trek: about 88 km over nine trekking days, two nights near or above 4,500 m, glacial moraine walking along the Zemu Glacier and no villages, shelters or rescue access after Zema. Operators call it strenuous and for seasoned trekkers only.
Photos
On the trail
The route
Day by day
Day 1
Bagdogra / New Jalpaiguri → Gangtok
120 m → 1,650 m
Day 2
Gangtok → Lachen
1,650 m → 2,730 m
Day 3
Lachen (drive to Zema bridge) → Tallem
2,730 m → 3,240 m
Day 4
Tallem → Jakthang
3,240 m → 3,430 m
Day 5
Jakthang → Yabuk
3,430 m → 4,040 m
Day 6
Yabuk → Rest Camp
4,040 m → 4,570 m
Day 7 · highest point
Rest Camp → Green Lake
4,570 m → 4,935 m
Day 8 · highest point
Green Lake → Green Lake (rest and explore the Zemu Glacier moraine)
4,935 m → 4,935 m
Day 9
Green Lake → Yabuk (via Rest Camp)
4,935 m → 4,040 m
Day 10
Yabuk → Jakthang
4,040 m → 3,430 m
Day 11
Jakthang → Lachen (via Tallem and Zema)
3,430 m → 2,730 m
Day 12
Lachen → Gangtok
2,730 m → 1,650 m
Day 13
Gangtok → Bagdogra / New Jalpaiguri
1,650 m → 120 m
Ups and downs
Altitude profile
Where it is
Map
Trailhead and high point only — not a recorded track. Use it with a proper map.
Weather
Next 5 days on the trail
Live forecast for the trailhead and the high point. Mountain weather changes fast — check again on the morning you start.
Trailhead · Lachen
at 2,730 mLoading forecast…
High point · Green Lake, beside the Zemu Glacier (approximate position)
at 4,935 mLoading forecast…
Each day: high / low °C · rain mm and chance · snow cm · wind km/h
Weather data: Open-Meteo.comModel forecast, not an official warning. For alerts follow IMD and the local administration.
Plan the trip
How to reach
- Trailhead
- Lachen
- Nearest railway
- New Jalpaiguri (NJP)
- Nearest airport
- Bagdogra Airport, Siliguri (Pakyong Airport near Gangtok has limited flights)
- By road
- Bagdogra / NJP to Gangtok (about 125 km, 4-6 hours); Gangtok to Lachen (about 120-135 km via Mangan and Chungthang, 5-7 hours; light vehicles must clear the Toong check post by 4 pm)
- Drive
- About 11 h from Siliguri
Plan the trip
Permits and fees
We could not confirm the current permit rules and fees from an official source. Check with the local forest department or tourism office before you go.
Plan the trip
Cost
Self-guided
₹50,000–90,000
With an operator
₹81,900–1,53,500
Per person. Guided prices published October 2026: Himalaya Shelter ₹78,000 + 5% GST (about ₹81,900) for 13 days ex-NJP/Bagdogra; Adarsh Tours, Travels & Expeditions (listed on Pelago) from ₹1,53,453 for a 16-day package ex-Bagdogra with Gangtok hotels. Other operators (Himalayan High, Black Yak Expeditions, East Himalaya) quote on request by group size. A truly independent trip is not possible: the restricted-area and trekking permits are issued only through a registered Sikkim agency, so the 'self-guided' range is an estimate for a small group that books a local Gangtok/Lachen agency for permits, liaison/guide, cook, porters or yaks, tents and food, plus shared transport ex-Gangtok.
Gear
Top picks for this trek
The gear that matters most on this route, chosen from its altitude, season and risks.
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Packing checklist
Matched to this trek: altitude, season, days and the risks on the route.
Packed 0 of 35
Nights near 4,935 m can drop close to freezing even in summer. Pack one more warm layer than you think.
Tick each item as it goes in the bag.
Know before you go
Good to know
- Mobile network
- Patchy mobile signal in Lachen; expect no network on the trail beyond Zema for the whole trek.
- Last ATM
- Mangan or Gangtok; carry enough cash from Gangtok, as Lachen has no reliable ATM.
- Nearest hospital
- Primary health care at Chungthang; District Hospital Mangan; STNM Hospital, Gangtok for serious cases. Evacuation from the upper camps means carrying the patient down to Zema.
- Water
- Zemu Chu and side streams along the valley up to Yabuk; glacial melt and small pools near Rest Camp and Green Lake carry heavy silt. Boil or filter all water.
Highlights
- Close views of the rarely seen east face of Kangchenjunga at the head of the Zemu Glacier
- Walking along the Zemu Glacier, the largest glacier in the Eastern Himalaya
- Green Lake camp at about 4,935 m, surrounded by Siniolchu, Simvo, Nepal Peak and the Kangchenjunga massif
- Very few permits are issued, so the valley sees only a handful of trekking parties a season
- Fir, birch and rhododendron forest of Khangchendzonga National Park between Zema and Jakthang
Risks
- Restricted border area: permits need Ministry of Home Affairs and defence clearance through the Sikkim Tourism Department and can take months; trips are cancelled when clearance is not given.
- North Sikkim roads are prone to landslides and washouts (2023 Teesta flood, June 2025 Chaten landslide, April 2026 bridge collapse); the Gangtok-Lachen road has closed for weeks at a time, so keep buffer days.
- Altitude above 4,500 m with no quick descent route; acute mountain sickness is a real danger without acclimatisation days.
- Monsoon (June-August) brings heavy rain, leeches and landslides on the approach; winter snow closes the upper valley.
- Moraine and glacier-edge walking near Green Lake has loose rock and hidden crevasse-like gaps; stay with the guide.
Know before you go
Questions
Is the Green Lake trek open after the Teesta floods?
Tourist permits for Lachen resumed in 2026 after the long closure that followed the October 2023 Teesta flood, and the Taram Chu route to Lachen reopened on 29 August 2026. Green Lake itself has never been an open trek: each party needs special clearance, so check with a registered Sikkim operator whether permits are being issued for your dates.
What permits are needed for Green Lake?
The Sikkim Tourism Department says the Green Lake trek needs a trekking permit from the Tourism Department with clearance from Defence and the Ministry of Home Affairs, New Delhi. Operators add a Khangchendzonga National Park forest permit. Permits are issued only to groups through registered agencies, and operators advise planning 4-5 months ahead.
When is the best time for the Green Lake trek?
April-May and late September to November. Operators run it in the pre-monsoon and post-monsoon windows; October and November give the clearest views of Kangchenjunga.
How difficult is the Green Lake trek?
It is a strenuous trek for experienced trekkers: about nine walking days, camps at 4,000-4,900 m, and moraine terrain along the Zemu Glacier. Some operators do not take trekkers under 18.
Where does the Green Lake trek start?
From Lachen in North Sikkim, about 120-135 km from Gangtok. Most groups drive a short way from Lachen to Zema, where the Zemu Chu meets the Lachen Chu, and start walking towards Tallem.
In an emergency
Save these numbers before you lose signal. Tap to call.
- 112All emergenciesIndia’s single emergency number — works in every state
- 108Ambulance
- 1077District disaster control room
You are in
District: Mangan (North Sikkim)Sikkim
- Nearest hospital
- Primary health care at Chungthang; District Hospital Mangan; STNM Hospital, Gangtok for serious cases. Evacuation from the upper camps means carrying the patient down to Zema.
- Last ATM
- Mangan or Gangtok; carry enough cash from Gangtok, as Lachen has no reliable ATM.
- Phone network
- Patchy mobile signal in Lachen; expect no network on the trail beyond Zema for the whole trek.
Before you set off
- Tell someone your route and when you will be back.
- Carry a charged phone and a power bank.
- Download an offline map of the route.
- Turn back if the weather turns bad — the mountain will wait.
Questions about Green Lake
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Where this comes from
Sources
Last reviewed:
- Adventure Tourism – Tourism & Civil Aviation Department — Tourism & Civil Aviation Department, Government of Sikkim (official)
- Sikkim: Lachen reopens for tourists, restricted vehicular movement timings — NewKerala (IANS)
- Green Lake Trek — Himalaya Shelter
- Green Lake Trek (North Sikkim) – 11 days — East Himalaya
- Green Lake Trek Sikkim — Himalayan High
- Sikkim Green Lake Trek — Black Yak Expeditions
- North Sikkim Green Lake Trekking (Adarsh Tours, Travels & Expeditions) — Adarsh Tours, Travels & Expeditions (via Pelago)
- Green Lake Sikkim: Travel Guide — WanderOn
Photos: Carsten.nebel, CC BY-SA 3.0; Amitabha Gupta, CC BY 4.0
