The Old Man and the Sea takes place in a fishing village near Havana, Cuba in the late 1940s. Santiago’s very modest home is described, as are some of the village’s fixtures: for example, a local restaurant called The Terrace. This setting highlights Santiago’s poverty, which in turn underscores the significance of his recent string of "bad luck" (days without catching a fish).
Most of the story takes place on the waters of the gulf of Mexico. Specifically, the bulk of the story is Santiago alone on his skiff out at sea. This hostile setting frames Santiago as he fights to survive. Nature, however, simultaneously provides for Santiago: he calls the fish his "friends," and he sustains himself on a dolphin he catches and the shrimp he finds on Sargasso weed.
The fact that Santiago is alone, which is to say not with the young boy Manolin, is both a function of the setting and a major through-line of the story. This isolation allows the battle between fish and man to be particularly powerful—it is Santiago versus the marlin—while simultaneously highlighting the relationship between Santiago and the fish he catches. Santiago has admiration for the marlin, ultimately viewing him as akin to a "brother," and he ends up claiming he doesn’t care whether he or the marlin dies. The absence of Manolin also highlights the age of Santiago and the weaknesses that come with aging, which make his battle against the marlin more difficult.