Citizen science should adhere as much as possible to the ideas of open science. On the topic of data sharing, the FAIR principles could be applied, making data as open as possible and as closed as necessary. However, it is unclear how open participants want to be with health-related data that is collected as part of a citizen science project. The current study is a first investigation of this topic with a multidisciplinary group of stakeholders and experts in a citizen science for health project. In two focus group discussions we discussed the views and desires regarding the sharing of data and the preferences for the levels of openness when sharing. The results of this study provide preliminary preferences regarding openness; people find sharing of data important yet not all are comfortable with making data completely open. Therefore, it was chosen to share metadata of our projects in repositories, and provide the full, anonymized or pseudonimized, dataset upon reasonable request. Future research needs to be done to confirm the current findings and to investigate the preferences of a broader group of participants in citizen science for health.