Unsymmetric composite laminates are potential candidates for applications in morphing structures due to bistable characteristics that manifest large deformation between the two stable states. For its integration to a larger structure, it is important that specific boundary conditions are imposed at its edges. However, applying boundary conditions leads to a drastic change in the strain energy landscape, resulting in a loss of bistability. This indicates a strong interplay between geometrical parameters and boundary conditions. Therefore, the potential of any multistable structure can only be realised through external connections (boundary conditions at edges). In this work, we propose a three-sectioned laminate that remains bistable under simply supported boundary conditions at the edges. Through numerical analysis, we explore the influence of boundary conditions on the bistable behaviour of composite laminates, considering both single-section (purely unsymmetric) and three-section configurations. A comparison of the bistable behaviour of both types of laminates is also conducted. Later, FE results are also validated by making a semi-analytical model, and good agreement is observed between them. The findings of this study contribute to a better understanding of the underlying mechanisms governing the behaviour of multistable structures under an imposed boundary condition, thereby aiding in the design and optimisation of such structures for diverse applications.