The research undertaken in this thesis is concerned with the design and development of Proton Exchange Membrane (PEM) fuel cells and provides a body of information for continued PEM fuel cell development, which will ideally aid in the future commercialisation of these electrochemical devices. Through a combination of numerical analysis, computational fluid dynamic modelling and experimental work, effective flow plate designs, flow field configurations and materials are analysed and new innovative designs are proposed. The flow plate of a PEM fuel cell is one of the most important structures in these devices. Effective design of the flow plate will aid in the optimisation of PEM fuel cell technology. Due to the low operational temperature of PEM fuel cells, water species can form in the flow field and this can affect their performance. Two phase flow models were used to study this phenomena. These models show how the water flooding in flow field channels can hinder the mass transport if these are not properly designed, leading to reduced performance, increased heat and reduced fuel utilisation. A high speed camera technique in an ex situ apparatus was used to validate the model and water mitigation methods are proposed. From the culmination of the analysis performed a novel application of open pore cellular metal foam as a flow plate material is proposed in this thesis. A model is developed, to simulate this relatively new material and extensive pressure analysis and flow modelling has been completed using this model. Computational fluid dynamic modelling, with an additional electrochemical PEM fuel cell module, has been carried out on conventional double channel flow plates and open pore cellular foam flow plates. Flow regimes, pressure analysis, water accumulation, oxygen concentration, fuel utilisation, current & voltage curves and cell temperature profiles are analysed. The PEM fuel cell model with open pore cellular metal foam flow plate performs in excess of a 55% improvement on the current density of the bench mark double serpentine flow plate under the same operating conditions at 0.7 volts. All of the above multi physical phenomena match very well to the experimental results. This information is new to the area and should help optimise PEM fuel cell performance.