The aim of this research is to propose a model of SA andinteraction in virtual environments of the relationshipamong immersion, presence, situation awareness, andperformance. The research presents an experiment toexamine presence, task/user performance and SA withdifferent VE interface designs (hybrid 2D&D, 3D nonnaturalistic,3D naturalistic) and head tracking system(non-tracking, tracking). The interrelationship amongimmersion, presence, SA, and performance is alsoinvestigated. The results from VRSARM and VRSAGATindicated that the participants, who felt present andimmersed, exposed to hybrid 2D&D were moresituationally aware than those who exposed to 3D nonnaturalisticand 3D naturalistic. By using sicknessquestionnaire, the participants who exposed to 3D nonnaturalisticexperienced higher sickness symptom thanthose who exposed to hybrid 2D&D and 3D naturalistic.There were no significant main effects on recall measure,VRSAGAT, or presence. VRSARM indicated that therewas a significant correlation between immersion andpresence (r = 0.66, ρ < 0.000), presence was positivelycorrelated with SA (r = 0.373, ρ < 0.003), and immersionwas positively correlated with SA (r = 0.532, ρ < 0.000).However, there was no significant correlation betweenpresence and performance or SA and performance. It wastherefore concluded that presence does not lead toenhance performance, and the relation between SA andperformance is not apparent. Nevertheless, thisexperiment is used to generate design implications forfuture directions for SA in VE in which associationsbetween variables might be found based on the IPSAPmodel presented here.