Carisbrook Falls lie 7km west of Kennett River. To find them, look for the signs to the carpark (turn right heading west) just past Cape Patton Lookout. The walk to the falls is a leisurely 10 minute walk from the Great Ocean Road. When I visited, rain was threatening, so I walked quite quickly and got there much quicker than 10 minutes; it actually seemed less than 5 minutes.
Carisbrook are one of the highest falls in the Otway Ranges, but they do not fall vertically, rather they rush down a diagonal rock face. The falls are impressive enough, but the viewing platform is a fair way back, and the falls are slightly obscured. I'd really love to see the path continued around to the right of the falls, as the view from there looks like it would be quite good.
Access along Carisbrook Creek is neither signposted, or advised. It looks pretty rough down there!
The best time to view them is after heavy rain; they aren't quite as impressive in the drier months.
While they are not the most visited or impressive falls, their close proximity to the Great Ocean Road, and the short easy walk make them still worth a look.
Two other nearby waterfalls of note are Sheoak Falls and Cumberland Falls, both of which are just past Lorne. Sheoak Falls are similarly close to their carpark, and the walk is leisurely, while Cumberland Falls require a 6km challenging return walk which involves numerous river crossings. Cumberland falls, and the valley walk to get to them are very beautiful, so you are rewarded for your effort.
Carisbrook Falls --> Great Ocean Road Homepage
Carisbrook Falls --> Beautiful Waterfalls Page