This paper investigates an appropriate choice of anchor currency for a proposed Melanesian currency union under various hypothetical currency union arrangements. Drawing from the optimal currency area (OCA) theory and related extensions, the analysis focuses on the effects of a currency union on exchange rate volatility following similar approach by Scrimgeour (2002). Counterfactual exchange rate series are constructed for alternative scenarios for Melanesia with the following major trading partners: Australia, New Zealand, USA and Japan. The main findings showed that both short-term and cyclical exchange rate volatility are generally lower in a currency union with either Australia or New Zealand. However, the results vary under varying weights and currency baskets. Choosing a single common anchor currency based solely on exchange rate volatility may not be conclusive. Hence, further research is required, for example, in considering the effects of a currency union on volatility in output, inflation or interest rates.