Mental wellbeing is the combination of feeling good and functioning well. Digital technology widens the opportunities for promoting mental wellbeing, particularly among those young people for whom technology is an ordinary part of life. This paper presents an initial review of publicly available apps and websites that have a primary purpose of promoting mental wellbeing. The review was in two stages: first, the interdisciplinary research team identified and reviewed 14 apps/websites, then 13 young people (7 female, 6 male) aged 12–18 years reviewed 11 of the apps/websites. Overall, the reviewers’ views were positive, although some significant criticisms were made. Based on the findings of the study, initial recommendations are offered to improve the design of apps/websites for promoting mental wellbeing among young people aged 12–18 years: highlight any age limits, provide information on mental wellbeing, improve findability, ensure accessibility on school computers, and highlight if young people were involved in design.