Various studies have assessed animal welfare by analysing how behaviour is affected by environmental and human-related factors. Nevertheless, the combined effects of these factors are poorly researched. This study assessed for the first time the integrated impact of environmental conditions and visitor and caregiver presence on the behaviour of a pair of zoo- housed Asian small-clawed otters. We collected data across 14 sampling days from July to September 2020. We video-recorded the otters’ behaviours using continuous focal animal sampling (42 h of observation/subject). We found that the otters only performed species-specific behaviours and mainly experienced positive welfare states. However, they dedicated less time to locomotion, food-related and affiliative behaviours, and engaged more in vigilance compared to previous studies carried out in captive settings. Interactions between the otters and visitors/caregivers were limited and mostly associated with neutral or positive behavioural responses. Visitor presence and background noise did not affect behaviour. Time of day and animal identity influenced locomotion, vigilance, time spent out of sight, juggling, and visitor–otter interactions. Our results provided meaningful information to improve husbandry practices and highlighted the need to conduct multivariate analysis to better assess the welfare of animals under human care.