We consider analytically and numerically the welfare tradeoffs inherent in a preferential trade area (PTA) with products differentiated by region of origin. For a small open economy in such a setting, welfare gains are associated with higher trade volumes within the PTA. However, welfare losses are induced by declining tariff revenues on trade with non-member countries. We show that both effects are concave, while one is a non-monotonic and the other a potentially non-monotonic function of pre-PTA partner trade shares. Therefore, the relationship between initial partner import shares and direct static welfare impacts of a PTA are theoretically ambiguous. This finding contrasts with conventional results in the homogeneous-goods case, whereby the smaller is the pre-agreement trade volume with a potential partner the more beneficial is a PTA.