Technical innovations are transforming our ability to estimate population size and status. Hares (Lepus spp.) are cryptic species, often nocturnal or semi-nocturnal, and thus they may be challenging to monitor. Here, we assess the combination of distance sampling with thermal imaging to improve the population monitoring of hares. Three study areas in central Sweden were selected based on presumed hare occurrence across agricultural, mixed, and forested habitats. Each area was surveyed five times from November 2022 to February 2023, during daylight along a total of four 1-km transects using thermal imaging binoculars with regular 360° scans. Detected hares were approached for visual species identification and to obtain more precise estimates of the lay. Over the 15 survey days, 29 hares were detected, with 79% through thermal imaging. Only European brown hares (Lepus europaeus) were observed, with 55% found in forested habitats where detection would have been challenging without thermal imaging. Detection distances reached up to 315 m in open terrain and density estimates derived from distance sampling ranged from 0 to 8.1 hares/km² among the study areas. Our study demonstrated the potential for using thermal imaging to enhance detection probability in daylight and thus improving population estimates for wildlife management. In addition, the method enables e-DNA sampling from lays and the opportunity to identify habitat preferences and behaviours of cryptic species like hares.