One of the easiest and most satisfying half-day trips from Bled is to Vintgar Gorge, some 4km to the northwest of Bled village. The highlight is a 1600m wooden walkway through the gorge, built in 1893 and continually rebuilt since. It criss-crosses the swirling Radovna River four times over rapids, waterfalls and pools before reaching 16m-high Šum Waterfall.
The entire walk is spectacular, although it can get wet and slippery. There are little snack bars at the beginning and the end of the walkway; the path to view Šum Waterfall is behind the kiosk at the walkway's end.
It's an easy walk to the gorge from Bled. Head northwest on Prešernova cesta then north on Partizanska cesta to Cesta Vintgar. This will take you to Podhom, where signs show the way to the gorge entrance. To return, you can either retrace your steps or, from Šum Waterfall, walk eastward over Hom (834m) to the ancient pilgrimage Church of St Catherine (signed 'Katarina Bled'), which retains some 15th-century fortifications. From there it's due south through Zasip to Bled. Count on about three hours all in.
In July and August, buses leaves Bled bus station daily at 8.30am, 9.30am and 10.30am for Vintgar, stopping at several points in town, including Bled Castle, along the way.