This hike has a long, tough first day, and a quick descent on the second day. It is better set up for visiting the Eisriesenwelt. See also the reverse direction.
A nice loop around the Tennengebirge from Werfen, stopping at the Werfener Hütte for the night. I did this hike years ago, and I'm looking forward to the opportunity to do it again! See the directions below for logistics: it costs around €40 each by train, or €40 per car, meaning it looks cheaper to rent than for three people to take the train. Thanks, ÖBB!
If you're feeling touristy, you could visit Eisriesenwelt (a cool ice cave) too, but note that it's part of the first, longer day (15km, 2000m ascent).
I took the photograph of the hut from a light propeller plane back in 2015.
~ Charlie Harding