This paper investigates the effect of EU enlargement on net FDI inflows of member countries using a panel data fixed effects model. We found that 27 EU members are associated with a positive change in FDI net inflows, but countries signing bilateral FTAs with the EU are not. By comparing with multilateral and bilateral RTAs in the EU enlargement case, we found that signing bilateral FTAs leads to more FDI inflow to member countries. In addition to market size, GDP growth rate, and openness, FDI inflow increases with the growth rate of TFP and global FDI net inflows. The conclusion implies that, facing Asian Pacific regional economic integration, Taiwan may promote FDI inflows by signing bilateral FTAs with TPP and RCEP Members before entering TPP and RCEP.