A need for highly effective vaccines against malaria has been made more urgent following stagnation in reduction of the global burden of malaria in recent years and COVID-19 pandemic related increases in malaria burden following disruption of currently available control measures. While advances in Plasmodium falciparum malaria vaccine development have seen the recent approval of the RTS,S vaccine, limited progress has been made towards development of a vaccine against P. vivax. Currently, no vaccines for P. vivax have completed testing for efficacy in malaria-endemic settings and limited candidates are in the discovery pipeline. One of the major challenges to developing a P. vivax vaccine is a limited knowledge of the targets of functional immunity. Antibodies against malaria play an important role in acquired immunity and are likely to act through three major mechanisms: direct inhibition, recruitment and activation of complement, and interactions with Fcγ-receptors to promote phagocytosis by immune cells. A role for the functional antibody mechanisms in P. vivax immunity remains unclear. We have recently developed novel high throughput multiplex assays to identify the targets of functional antibodies against P. vivax that interact with complement and Fcγ-receptor. In a longitudinal cohort study of 1–3-year-old children from PNG, we measured both antibody magnitude (IgG, IgG subclasses and IgM) and antibody function (complement fixation, FcR binding, opsonic phagocytosis and avidity) to 30 P. vivax antigens. Using these approaches, we identify both known and novel antibody targets and functions for associations with protection against clinical P. vivax malaria. Using statistical modelling approaches we identify important combinations of antigen-specific antibodies, both magnitude and function, that may provide maximal protection against P. vivax malaria. Our findings identify promising antigens for prioritisation and advancing in P. vivax vaccine development, and knowledge of functional immune responses that are most important for protective P. vivax immunity.