Measuring capacity and capacity utilisation at seaport terminals is essential to ensure efficient utilisation of the infra- and superstructure of the seaport. Most of the methods that have so far been used to measure capacity utilisation are not easy to comprehend for a common seaport operator. Most of the methods are also data intensive and therefore not suited for developing countries. This article attempts to use well-known standard queuing models to measure capacity utilisation in a seaport using the seaport of Dar es Salaam (Tanzania) as a case study. Historical data on terminal performance for the general cargo and the container terminal have been collected to validate the model. Based on standard queuing models it has been found that terminal capacity for both terminals is being underutilised and that, as a result, ships are being subjected to unnecessarily long waiting times; a conclusion backed up by a more detailed simulation model. Although some assumptions on which common queuing models have been derived may not hold true in practice, it is argued that standard queuing models can be used as a quick scan for evaluating seaport terminal capacity utilisation. If accurate measurement is needed, more data may need to be collected to determine the actual ship arrivals and service time distributions and develop an appropriate simulation model. The methodology developed in this article, although validated using port performance data for the port of Dar es Salaam, is directly applicable to any other seaport. © 2014 Macmillan Publishers Ltd.