Sea of Ice: Exploring France’s largest glacier, Mer de Glace

20 July 2017

Last Updated on 9 February 2021

Since I finished my Tour du Mont Blanc hike several days ahead of schedule, my friend Katy and I have a few days of just hanging out in Chamonix before we fly to Spain. One of these days, we decide to visit the Mer de Glace, recommended to Katy by a retired Australian couple she met while I was hiking.

Mer de Glace, or Sea of Ice, is France’s largest glacier, measuring 7km in length and more than 200m in depth, and is also the second largest glacier in the Alps. Apparently it was once large enough to be visible from the Chamonix Valley, but considerable shrinkage now means that we must travel out towards the Mont Blanc massif to see this amazing piece of nature. (Once at the viewing platform, we learn that the glacier is moving more than 100m every year, which seems quite inconsequential until you realise it’s about 1cm every hour!)

All the details: Mer de Glace

Cost: 33.5€ will get you return tickets from Chamonix to the Mer de Glace, as well as a ride on the gondola and entry to the ice caves.

Getting there: From the little Montenvers station in central Chamonix, catch one of the charming red trains up to Mer de Glace. You can purchase tickets directly at the station on the day, and these include both the transport and entry to Mer de Glace.

Top tips: You can visit Mer de Glace most any time of year (and there are actually some great hikes that will take you by this beautiful place), but be aware that the ice caves have a limited window from June to September. Check out exact dates and times here before you plan a visit.

From Chamonix, we catch the cute little red Montenvers train, which climbs for about 20 minutes nearly 1,000m up the side of a mountain to reach Mer de Glace. The return trip costs about 31€, so we are both hoping that the famous ice cave will be worth the expense.

When we arrive, we spend a few minutes taking in the views over the receding Mer de Glace and the mountains before boarding a cable car and descending towards the ice cave. Once out of the cable car, there are 500 steps to descend (which proves a painful task for my knee, especially since I didn’t bring my brace). On the way down, plaques mark the level of the glacier at previous years― a sad but fairly inarguable testament to global warming.

We eventually reach the mouth of the ice cave and are immediately stunned by the volume of water trickling off in all directions. I’m actually not even sure “trickling” is the right word.. maybe more like “gushing”. We soon learn from a nearby sign that the glacier has lost about 800,000,000m3 of water in the last 70 years, which equates to about 30cm of height loss every single year. If you can’t picture just how dramatic that is, Google photos of Mer de Glace in the early 1900s and then compare to my photos..

Inside the ice cave, we are plunged into a freezing world of blue. We easily entertain ourselves for an hour just admiring the patterns of ice within the glacier and the amazing clarity of the frozen walls. I also entertain myself by licking the wall, because it looks so beautiful that I can’t resist.

There are even a few posters showing the glacier many years ago and it’s alarming to recognise just how much the glacier has shrunk over time. Mer de Glace is still beautiful, but it’s nothing like it was. And perhaps it will completely disappear one day, so I’m quite thankful to have set foot in this magical blue world while it lasts!