The Port Botany Expansion (PBE) project involves the construction of an extension to the existing port in Sydney, Australia. The transition between the new structures and the existing Brotherson Dock (EBD) structures is a critical aspect of the geotechnical design. The Client, Sydney Ports Corporation (SPC), specified tight differential movement and settlement limitations for the transition between the new and old structures, including a stringent 5mm differential movement limit (horizontal and vertical) up to 20 years after handover of the new terminal. The subsequent geotechnical and structural design of transition structures included measures to comply with these movement limits. The Main Contractor, Baulderstone Hornibrook – Jan de Nul (BHJDN) are carrying out construction trials, in situ testing and movement monitoring to assess performance against Golder Associates’ (Golder) design predictions. This paper describes the key design issues, design approach and verification processes established to confirm the predicted behaviour of the structures and surface infrastructure in order to satisfy criteria extending up to 50 years following handover.