This article aims to contribute to knowledge about the characteristics of a Visual Identity System, including a design exploratory study for the Museu Marítimo de Ílhavo, Portugal. The study focuses on Flexible Visual Identity Systems in the context of cultural organisations, particularly museums. The methodology includes non-interventionist components such as a literature review, a descriptive case study, direct observation, interviews, and active research through an exploratory case in a design project. The results contribute to knowledge about the seven components of a visual identity system, the essential characteristics of a Visual Identity System, namely flexibility and coherence, as well as the design process of a flexible visual identity system for cultural organizations.