Reliability of service times has long been a concern of many ports around the world. This paper presents an approach to mitigate delays in service times through improved information sharing in ports. The approach is based on a mapping of information sharing links and their association to the root causes of frequently occurring delays. We identify the kind of information which is critical in mitigating delays. Critical information links are then re-ordered to create an information sharing arrangement between the actors, which further condenses and simplifies the required information sharing actions. We apply the proposed approach to the Port of Rotterdam. Quantitative data of 28,000 port calls is complemented by qualitative data collected through direct observations and expert interviews with port actors, including the pilot organization, a tugboat company, the boatmen organization, the harbour master, a terminal and a vessel agent. Besides the suggested arrangement for information sharing, the case reveals the critical position of pilots, a vulnerable position of tugboat companies and the minimal contribution made by the terminal towards information sharing. The increased pressure on ports by ever larger vessels seems to bear its fair share for delays and bottlenecks in the smooth execution of port operations.