Power BI developers ensures data security by implementing best practices like role-based access control, data encryption, and secure sharing options. They configure Power BI’s security settings to restrict access to sensitive information, ensuring that only authorized users can view or modify data. The developer also stays updated on the latest security protocols and compliance standards, integrating these into the Power BI environment. By doing so, they help protect the organization’s data from unauthorized access, breaches, and ensure compliance with relevant regulations.