Changes in our society have created a challenge for policymakers, who confront a need of tools to evaluate the possible effects of their policies. Agent-based modelling and simulation is a promising methodology which can be used in the study of population dynamics. In this paper we introduce an agent-based simulation approach to project the population of Gambian migrants in Spain during 10 years. Our approach not only enables to simulate the life course of individuals, but also allows deeping on the movements, interactions, and behaviours of the target population. The model is able to capture individual characteristics and to overcome some data-related limitations with assumptions on behavioural rules. With this methodology, we want to show the potential of the tool with the study of a real case scenario.