This paper investigates the Japanese direct investment in Portugal overseas territories (or Provinces) and in its mainland. It shows the impact of Portugal’s integration into the European Economic Community that after the
1980s has contributed to the boost of the Japanese direct investment in Portugal. In addition, this paper explains the effects of Japanese FDI in Portugal through the affiliates regional sitting and typology in Portugal. Finally, it takes into account the relationship between trade and foreign direct investments of the main Japanese trade affiliate companies amongst the 100 biggest export and import companies established in Portugal in 1998 and
1999.