Yala's Block I is the most visited national park in Sri Lanka, and for good reason: dry-zone scrub, open plains, and a wetland belt pack in leopards, elephants, sloth bears, crocodiles, and well over 200 recorded bird species into a relatively compact area.
Two safaris — one at dawn, one in late afternoon — meaningfully improve your odds over a single run, since animals are most active in the cooler light at each end of the day.
Our guider positioned the jeep before the sighting even happened. Best two hours of the whole trip.
We did dawn and afternoon both. Dawn was quieter, afternoon is when we finally saw the leopard.