n recent years, Port and marine industry design standards were shifting their focus towards performance based and elasto-plastic limit state design criteria. Whilst performance based criteria for wharves and piers were well explained and covered by POLA/POLB1, performance based design of the dolphins was never reviewed. Current PIANC WG-332 only briefly discussed design of the flexible dolphins. Some of the WG-33 statements related to fender supporting structures are ambiguous, and not well understood. In authorâ€™ opinion, PIANC provisions do not differentiate between rigid, semi-flexible and flexible dolphin systems making conflicting statements. The following study covers several aspects associated with design of semi-flexible and flexible dolphin systems, and addresses design issues which were insufficiently covered by PIANC and national marine codes. The list of covered issues includes: â€¢ fender selection conflicts â€¢ concept of impact dynamic amplification â€¢ utilization of the ductility concept for performance based design criteria â€¢ the concept of capacity protected elements and proper application of overload factors â€¢ detailing mistakes in pile to pile cap connections. This paper reviews design of the flexible dolphin systems with concrete pile caps, explaining common design misconceptions and filling the gaps in the current design practice.