Positive psychology interventions hold great promise as schools around the world look to increase the wellbeing of young people. To reach this aim, a program was developed to generate positive emotions, as well as improve life satisfaction, mental toughness and perceptions of school kindness in 538 expatriate students in Dubai, United Arab Emirates. Starting in September 2019, the program included a range of positive psychology interventions such as gratitude, acts of kindness and mental contrasting as examples. Life satisfaction and mental toughness at mid-year were sustained or grew by the end of the year. Positive affect, emotional wellbeing and social wellbeing increased at post-intervention 1, compared to baseline. However, this improvement reverted to baseline levels at post-intervention 2, when data were collected during the COVID-19 pandemic. Only psychological wellbeing, negative affect, perceptions of control, and school kindness were increased at post-intervention 2. During the lockdown, students moved less, but slept and scrolled more. Those who extended their sleep duration reported greater wellbeing. Boosting wellbeing through the use of positive psychology interventions works - even in a pandemic - and extended sleep duration appears to be a driving factor for this observation.