são tomé and príncipe, officially the democratic republic of são tomé and príncipe is an island nation in central africa, it is located off the gulf of guinea. the main islands of são tomé and príncipe are about 140 km apart and about 250 and 225 km, respectively, off of the northwestern coast of gabon. the country have a population of 201,800 (2018 official estimate),são tomé and príncipe is the second-smallest and second-least populous african sovereign state after seychelles as well as the smallest and least populous portuguese-speaking country in the world.