This series of working papers presents the ongoing analysis of the mobility behaviour in Switzerland during the period of special measures to combat the Corona virus. A sample of over 1200 participants was recruited from a previous GPS-based mobility study, MOBIS. A 4 week baseline period is therefore available for each participant from the second half of 2019, as well as socio-economic variables. Mobility indicators considered include modal splits, hourly counts, average daily distances, activity spaces and daily-radius. First results indicate drastic changes in mobility behaviour, with identifiable differences between socio-economic groups. The analysis continues to be updated as the situation progresses