Evidence suggests that mental health problems in young people have been exacerbated by COVID-19, possibly related to a lack of social connection. Young people report using the internet for connecting with their peers and mental health support. However, how they may have used the internet for support during COVID-19 is not clear. We wanted to know how mood and internet use may have changed in young people during COVID-19 and if this was different for those with and without depression symptoms. 108 adolescents were recruited. Participants with high and low levels of depressive symptomatology answered questions about their mood, internet use, loneliness and life satisfaction during July and August 2020. We found that the high depression group reported significantly more loneliness and less life satisfaction than the low depression group. We found that most young people used the internet for mental health information during COVID-19 but that the high depression group used the internet more for mental health information than the low depression group. The high depression group also had a worsening of mood compared to the low depression group during COVID-19. We found that Black, Asian and Minority Ethnic participants reported increased use of the internet compared to White participants during COVID-19 and that the role of the family facilitated coping during COVID-19 for some adolescents, but for others, it made the lockdown more difficult. Finally, we found that adolescents perceived school anxiety as stressful as COVID-19. To conclude this study supports the use of the internet as a way to help young people with mental health challenges. It also suggests that the internet is a way to help young people from ethnic minorities, who otherwise might be hard to reach, during challenging times. This study also shows that supportive family units can be important during times of stress for young people and that school anxiety is a major issue for young people in today’s society even outside of the pandemic.