Mobile games are a pervasive and understudied facet of human culture. Here, we provide a first glimpse into cross-cultural patterns in mobile playtime using a dataset of 118 billion hours of human gameplay telemetry, spanning 184 countries and 3 years. Results showed substantial variations in average playtime across countries, largely explained by country-level variance in GDP per capita. Once GDP per capita was controlled for, substantial residual variance was observed in the playtime of African and South Asian countries, and smaller residual differences were observed in Latin American and Middle Eastern countries. These residual differences were not related to Hofstede’s six dimensions of cross-cultural psychology, nor were they related to a variety of country-level factors such as median age, internet penetration, or inequality. This suggests that they are either due to unobserved heterogeneity in the composition of users, or that they reflect as-yet-uncharacterised dimensions of cross-cultural psychology.