Background: The COVID-19 pandemic has resulted in many countries enforcing a ‘lockdown’, whereby people are instructed to stay at home. Aim: The aim of this study was to capture the experience of such a lockdown in Australians living alone, with and without a dog or a cat. Method: Three hundred and eighty-four participants completed an online survey evaluating their levels of loneliness, mindfulness and mood. For participants who owned a dog or a cat, a measure of dog/cat interactions was also administered as well as two open-ended questions about how being a pet owner affected their experience of COVID-19 and how COVID-19 affected their pet. Results: Contrary to expectations, cat owners were found to be less mindful than non-owners and pet interactions did not account for levels of loneliness or levels of mindfulness. In line with our expectations, however, stress and depression positively predicted loneliness, while mindfulness and being a dog owner were protective against it. Insights from qualitative responses suggest that this might be due to the fact that dogs encourage a routine which involves getting out of the house and walking, which itself offers opportunities to socialise with other people doing the same thing. Conclusion: These findings add to the emerging literature on mental well-being during a lockdown and the unique role that pets play in their owners’ experiences.