Blue marlin (Makaira nigricans) have been documented to undertake long – and sometimes transoceanic – migrations, according to electronic pop-up satellite archival tag (PSAT) data obtained primarily in the western North Atlantic, with additional reported deployments from selected locations in the Pacific. Information on the movements of blue marlin in the South Atlantic, however, is lacking, despite evidence of spawning aggregations off the coast of Brazil during the Southern Hemisphere’s late spring and summer. Additionally, there are no reported long-term PSAT tag deployments on blue marlin in the western South Atlantic. Therefore, their movements in that large area remain unknown. Through a combination of literature review and limited PSAT tagging, this paper provides a comprehensive analysis of the movements of blue marlin in the South Atlantic. Of particular interest is evidence of interaction between the South and North Atlantic blue marlin populations, as further evidence that there is no significant genetic population structuring within the Atlantic Ocean for this species. As a secondary objective, this paper provides a quantitative comparison of blue marlin surface temperature preferences in the Atlantic and Pacific, which serves as a determinant of habitat for this species.