The Once Only Principle (OOP) drives current public sector modernization through the reduction of administrative burdens. It requires public authorities not to ask citizens and companies to repeatedly provide information to the public authorities. Instead, public authorities shall share and re-use data among themselves in due respect of data protection regulation. The sharing and re-use of sensitive and non-sensitive data among public administrations demands for broad acceptance by all stakeholders. Trust and transparency are key success criteria in such data-driven public sector transformation. Establishing proper governance mechanisms for the data infrastructures that enable the sharing and re-use in public service provisioning, and that provide the necessary transparency and trust levels is expected to effectively improve public service. This research investigates approaches for establishing a good data governance in OOP settings tackling the sharing and re-use of sensitive or personal data. Geographical focus is on the European Union and Switzerland.