The coronavirus (COVID-19) pandemic has adversely affected individuals’ mental health. Social isolation as a result of social distancing during the pandemic potentially affects the associations among perceived available peer support, emotional well-being, and depression in university students. The present study examined the associations among perceived available peer support, emotional well-being (as indicated negatively by loneliness and negative affects, and indicated positively by positive affects and hope), and depressive symptoms in university students. During the 3rd stage of the outbreak in July, 2020, 255 students at a public university in Hong Kong participated in an online-based survey which assessed their perceived available peer support, emotional well-being, and depressive symptoms. Results showed that perceived available peer support negatively contributed to depressive symptoms; both negative and positive indicators of emotional well-being mediated the association between perceived available peer support and depressive symptoms. The university students showed signs of depressive symptoms, highlighting the need for preventive efforts and increased access to mental health care that supports the psychological and emotional needs of young people during the COVID-19 pandemic.