Since its establishment in 2002, the Preverenges Bird Island (Île aux Oiseaux) on Lake Geneva has rapidly become an ornithological hotspot in Switzerland, particularly for migratory waders (small stilt-like birds). However, the progressive formation of a tombolo – a sandbar connecting the island to the shore – is now severely limiting its isolation and the tranquillity essential to this resting area. The present study examines the site’s morphological evolution and evaluates the potential of various design solutions to restore its isolation. Hydrodynamic wave modelling was performed using the SWAN software, based on sediment properties, wave data, and bathymetry. The results show that even solutions involving a substantial reduction in the island’s area do not promise a significant change in sediment transport, which is relevant to tombolo formation. Given the trend toward Swiss lakeshore restoration, this case study provides a foundation for understanding tombolo formation and serves as an example of ecomorphological development. This work emphasizes the need for an integrated management strategy and long-term monitoring to achieve the site’s sustainable conservation.