Santiago (The Old Man): The story revolves around this down-on-his-luck Cuban fisherman, who serves as the novel's protagonist. In his youth Santiago had been a sailor, and traveled to Africa, where he saw the lions which figure so prominently in his dreams. The old man continually recalls the past -- of a victorious arm-wrestling match, of previous fish caught, of the aforementioned lions -- to give himself the strength to persevere through his three days of suffering at sea. Despite his simple, compassionate nature -- most evident in his interactions with the boy -- Santiago remains one of literature's finest examples of a character exhibiting what Hemingway called "grace under pressure." Even though only his marlin's carcass is left by the end of the story, Santiago may be considered victorious because he never quit, valiantly fighting off the sharks until there was nothing left to fight for.
Manolin (The Boy): This is Santiago's loyal young sidekick, who helps take care of the old man, even though his parents have ordered him to find a luckier fisherman to sail with. Whenever Santiago is not sailing, the boy faithfully remains nearby to listen to the old man's stories or bring him whatever Manolin thinks he may need. Although he is not with the old man physically during Santiago's journey, Manolin provides the old man with his primary inspiration to endure -- as if he were praying to give himself strength, Santiago continually meditates, "I wish the boy was here" (50). At the novel's end, Manolin appears to be the only character who realizes the significance of the tragedy Santiago has just been through, as he breaks down and cries several times. Fittingly, in the final image Manolin sits by the sleeping Santiago "watching him" (127).
The Marlin: This 18 foot, 1500 pound fish serves as Santiago's first great obstacle during his three day trial at sea. The marlin, who tows the old man's skiff across the sea for two straight days, parallels Santiago's struggle to endure as it stubbornly and honorably refuses to die. After the old man harpoons the marlin and attaches it to the outside of his boat, a series of sharks mutilate the fish by tearing out chunks of meat. By the end of the novel nothing remains but "the long backbone of the great fish that was now just garbage waiting to go out with the tide" (126).
The Mako Shark: This is the first shark -- the first of a series of ruthless antagonists -- to attack the dead marlin attached to Santiago's skiff. Although the old man successfully kills the Mako, the victory comes at a great price: the shark takes forty pounds of marlin meat, Santiago's harpoon and rope, and, most importantly, makes the marlin bleed again, ensuring that other sharks will soon appear.