To join one of our trips you rally should have comprehensive travel and medical insurance. We don't arrange or sell insurance.
For our treks and trekking peak expeditions in Nepal you need insurance that includes "hiking" to 6000m/7000m AND helicopter evacuation.
If trekking/climbing in India in theory helicopter evacuation is possible, in practice it usually doesn't happen. In Tibet there is no possibility of helicopter rescue.
For trekking peaks, do get the correct policy, even if we are only climbing for a day or two. Note "winter sports" is skiing; not needed for a trek.
Do read the fine print to ensure you are covered.
First talk with your household insurer, your medical insurer (especially if you live in the USA or Canada) or your travel agent. Your household insurer or your medical insurer should be able to offer a cheaper policy than a travel agent, however ensure it covers the specific activities, such as hiking or guided+roped mountaineering.
Trekking is Hiking, in insurance terms, and some policies cover up to 7000m, ie the summit of Aconcagua.
In general treks have a green or olive-coloured title.
Expeditions are guided and/or roped climbs and are in turquoise.
UK companies will only cover residents of UK-Ireland.
JS Insurance - specifically tailored for trekking between 2000-6000m
JS Insurance - mountaineering
STA Travel UK - their premier policy (no winter sports) covers guided mountaineering with ropes, and trekking to 6000m
Sports Cover Direct - covers trekking to 7000m and mountaineering, and also ahve topup policies to cover what isn't covered by other insurance
Dogtag UK - cover trekking and mountaineering
Adventures Insurance - trekking 4000-6000m
BMC - the British Mountaineering Council, especially if going to high peaks
HCCmis.com for trekking and mountaineering up to 7000m
Dogtag USA - cover trekking and mountaineering
STA Travel - trekking is covered, not mountaineering
IHI.com, based in Denmark - they used to have no exclusions; now they exclude roped climbing
And here is an adventure travel primer, with a handy link too.
I don't recommend Global Rescue; in general we are quite capable of getting you out, it is the heli evac and then medical expenses afterwards that are important.
The above should cover everything but it is also possible to get separate insurance deals, and if you are a frequent flier having lost luggage, trip cancellation insurance separate from medical insurance makes sense.