The swim event starts at 12:00. Registration (30CHF) is until 11:00.
Meeting point is under the angel in Zürich HB. At 09:20 we'll walk to the train leaving Zürich HB at 09:32 - arriving in Merlischachen at 10:37 (change at Arth-Goldau).
Some more information (as found in the link):
At this swim event, the fastest swimmers will be rewarded. Nevertheless, it is open for everybody who is confident that she/he is able to swim this distance in open water.
Last year, there were almost 350 participants; it took 90 min for the last to arrive.
The start is in Greppen. When we arrive in Merlischachen, we'll register and wait for the boat transport to Greppen. The clothes will be put in your backpack. During the swim, the backpacks are transported back to Merlischachen.
For the way back there are two hourly train connections back to Zurich (via Lurzern or Arth/Goldau). Most likely we'll be leaving back to Zürich at 13:37 or 14:21.