Swimming across lac Léman

AKA Lake Geneva to the English

During the heatwave last week (first week of July 2015) we decided to take the opportunity of a very warm Lac Léman  to swim from France to Switzerland. We are not superhuman so we left the "classic" traverse from Evian to Lausanne alone (13km) and headed for the narrowest section instead. From Nernier to near Prangins (3.5km according to the map)


Nernier is a small quiet and picturesque little village. The is minimal parking available so get there early in the holidays. We arrived at 9.30am and found somewhere fine. You can drive down to the water's edge if you need to drop off a boat but it's not easy and best avoided. There is a public toilet at the Port if you need one.

2015-07-02 10.04.55

We were a little worried about the various hazards the lake can present. We'd checked the weather forecast and there were no strong winds likely, go before 10.30am and the lake is most likely to be mirror smooth too. After this time the thermic breezes will start up adding some ripples. There is a regular ferry service which doesn't like to give way to anything but it's only an issue close to the port of Nernier, if you don't set off or arrive as it is docking or leaving it should not be an issue.


The temperature of the lake changes very quickly. Up to 2 °C from the morning until the evening on a hot day. It's easy to gauge with this website though.


The figure you need is the "Température eau 1m". On our day it was 21 °C which was fine without a wetsuit. The only hazards we encountered where the occasional small wakes from passing boats.

P1000304 big

The headland we landed on is private land, there was noone around though and it's not overlooked. There is a sign which politely asks that you don't venture beyond the beach.

2015-07-02 11.21.19

We used a GPS to track our actual route, this is my return swim (the two of us took turns swimming and paddling the canoe), we had been heading towards the wrong landmark so had to change direction half way! According to the GPS it was a 4km swim which took 1hr 15min.


Posted on by Gareth Jefferies

11 Responses to Swimming across Lac Leman

  1. Michael Greenwood says:

    Well Gareth,
    I take, as they say in England, my hat off to you and your college. If I ever do make it to this area, I might, after a good deal of training, go for a swim in Lac Annecy It must be down to your out door life.

    Great to hear that the company is doing well. The exchange rate is good at he moment. Long may this continue.

    Cheers Michael Greenwood

  2. Michael Parker says:

    Hello Gareth, swimming across Lac Leman is something I have wanted to do since I visited the Jazz festival in 2003. In my mad fantasy I was looking at Montreux to Evian (16km?) but your route seems much nicer and I cannot believe that I never thought of using a support canoe to get me back. (I had visions of passport problems). I would love to do this in 2016, do you do this in an organised way or just rock up when you are ready?
    I have done a couple of mile swims and found them quite easy, obviously 3.5km is at least twice that.

    • Gareth Jefferies says:

      We just turned up on a day when we were ready, the weather was perfect and work can do without us! It’s quite hard getting those three things to line up! We are lucky that we live near by and can take a morning off work if required.

  3. Ben Barham says:

    I’m the founder of the Lake Geneva Swimming Association

    We are the governing body that facilities attempts at the length of the lake (Villeneuve – Geneva)

    Fancy it?

    Site: lakegenevaswimmingassociation.com

  4. Frits Willem Bakker says:

    Hi Gareth,
    I am not an expert swimmer but took lessons in 2011 to actually swim from Evian to Lausanne in sept 2012. I recommend it now after your 3,5k swim. It is indeed 13k depending on currents. I was blessed with a beautiful day. And it goes very well with a charity: I picked up money for the disease of MS which had a cat with MS patients sail during my crossing. I am now looking at swimming from Evian to Montreux 😉

  5. Jaco says:

    Hi Gareth,

    I’ve been looking into open swim waters in the Lake Leman and I came across your blog post. Thank you very much for sharing and congratulations, very inspiring.
    Logistically speaking, I am curious whether you brought your own canoe or you rented it at Nernier or somewhere else.
    Thanks in advance for any tips,


  6. Emma askew says:

    Well done on completing this swim.
    Have just read this and am inspired to do the same, or a shorter swim.
    I live in Blonay so have access to lake at a narrow point.
    Could you give me some tips on training and what equipment I may need please?

    • Gareth Jefferies says:

      We waited until it was really warm so didn’t even need a wetsuit. The only equipment was our safety boat. It was a canoe, you could use anything I guess. I even know of people that have used a sailing dingy. I don’t suppose that is ideal though! All my swim training comes from this website and the resources they sell. http://www.swimsmooth.com/ Good luck!

Leave a Reply

Your email address will not be published. Required fields are marked *