One hour is enough for Three Sisters Islands.

Yes, an hour is plenty for a relaxed stroll across all three islands with photo stops.

The three islands are connected by short bridges, so you’re never walking more than a few minutes between them. The paths are compact — you can cover the whole loop in 20 minutes without stopping. Add 30–40 minutes for photos and sitting on a bench, and you’re still under an hour.

If you move at a very slow pace or stop at every single overlook, maybe 90 minutes. But that’s the high end. Anything past that and you’re just sitting, which is fine, but you don’t need more time than that to see everything.

You’ll have time leftover for the falls.