Srpenica · Soča Valley
The Soča runs 8-12 °C even in August. That's what makes it that colour, and why you go with people who know it.
the Soča beach, ten minutes on foot
There is a proper beach on the Soča here - shingle, shallow edges and deep green water under the footbridge. Ten minutes' walk from the door, free, and nobody to book with. Read the river safety notes on the Essentials page before you get in.
the warm river - the one to actually swim in
The Soča is spectacular and cold. The Nadiža is the opposite: shallow, slow and genuinely warm by comparison, which makes it the one to swim in rather than gasp in. Worth the drive on a hot afternoon, and much better with children.
rafting
Also kayak, canyoning and fly fishing. They advertise the longest zipline in Slovenia.
kayak school
Beginners included. The Srpenica run below the house is a classic.
canyoning
Abseil, jump and slide. Small groups, all kit provided.