The marlin suddenly surges, waking Santiago. In the darkness, he sees the marlin jump from the water, again and again. The jumps jerk the line, pulling Santiago face-first into the leftover dolphinfish meat from his meal. Santiago desperately holds onto the line with his back and hand. His left hand is cut open again, and Santiago wishes that Manolin were with him to wet the lines to reduce their friction.
The reopening of the wound in Santiago's hand again evokes Christ's stigmata, linking Santiago's struggle to Christ's. Neither Santiago nor Christ sought to escape their suffering, Instead, each chose to endure it, and in the process, transcend it.
Desperate not to lose his strength from nausea, Santiago wipes the dolphinfish meat from his face. He examines his hands, which look almost like raw meat, and tells himself that "pain does not matter to a man." He eats the second flying fish to regain his strength.
Santiago again uses his pride in himself as a man to derive the strength he needs to endure the pain in his hand. .
As the sun rises, the marlin begins circling the skiff. Santiago now slowly fights the fish for line, pulling it closer to the boat inch by inch. The struggle takes hours. Santiago begins to feel faint and black spots appear before his eyes. As the marlin passes beneath the skiff, Santiago gets a glimpse of its full size and is awed by how big the marlin is. He pulls the fish in closer and closer in order to harpoon it. The effort is immense, and it seems to Santiago that the fish is killing him. He tells the fish, "Come on and kill me. I do not care who kills who."
The struggle between Santiago and the marlin reaches its climax. Santiago's faintness and the marlin's slowly shrinking circles indicate that both are tiring and approaching death. Santiago considers the struggle more important than its outcome: the struggle to survive and overcome is more important than actually living or dying.
As the marlin comes in closer, Santiago takes out his harpoon. He tries several times to harpoon the marlin, but misses, growing weaker and weaker. Finally Santiago draws all his strength, pain, and pride together and plunges the harpoon one last time, driving it into the marlin's heart. The marlin makes a final leap, glistening in the light, then falls into the water, dead. The marlins' blood stains the water red.
Santiago estimates the marlin weighs about 1500 pounds, too big for Santiago to pull inside the boat. Santiago lashes the marlin alongside the boat.
In death as in life, the marlin is Santiago's companion, literally traveling by Santiago's side.
As he works, Santiago thinks about how much money the marlin will bring, then imagines how proud of him DiMaggio would be. He wonders if his injured hands are comparable to DiMaggio's bone spur.
Santiago's thoughts about money are dwarfed by his pride in his ability to fight off pain and resist defeat.
Santiago begins sailing southwest, toward Cuba. He is hungry, and eats some tiny shrimp he finds living in a patch of yellow Gulf weed floating in the water. He takes the second-to-last gulp of water from his water bottle. Nonetheless, he becomes light-headed and wonders if he is bringing in the marlin or if it is bringing in him. He keeps glancing at the marlin as he sails. His injured hands prove that his struggle with the marlin was no dream.
It's clear that Santiago remains connected to the marlin, even in death. In fact, at times Santiago seems to think that he is the one that has died after the ordeal. The injuries that plagued him are now the only things that he can count on as real.
An hour after Santiago killed the marlin, a big Mako shark appears, having caught the scent of the marlin's blood. As the shark bites the dead marlin, Santiago rams his harpoon into the shark's head. The shark thrashes, dies, and sinks, but the harpoon rope breaks and Santiago's harpoon is lost with the shark.
Santiago's stabbing of the shark in the head, rather than the heart, suggests that he does not feel the same emotional connection or affinity with the shark as he did with the marlin.
The shark's bite took a 40-pound hunk of flesh from the marlin. More blood now pours from the marlin into the water, which Santiago knows will only attract more sharks. It seems to Santiago that his battle with the marlin was worthless, since the sharks will just come and eat the marlin. But Santiago quickly reminds himself that "a man can be destroyed but not defeated."
Santiago tries to remain hopeful. He considers it silly, or even sinful, to not be hopeful. But he begins to wonder whether it was a sin for him to kill the marlin. He knows that he did not kill the marlin just to feed himself and others, but also out of pride and love. He wonders whether it is more or less of a sin to kill something you love. He feels no guilt, however, for killing the shark, because he acted in self-defense. It occurs to him that "everything kills everything else in some way," but then he reminds himself that it is Manolin who keeps him alive.
Santiago leans over, strips off a piece of the marlin from where the shark bit it, and eats it. The meat is of the highest quality and would have fetched a good price. He sails on, eating pieces of the marlin in order to remain strong.
When Santiago eats the marlin, he and the fish become one, and the marlin lives on through Santiago. This recalls the Eucharist, in which Christ asks his followers to symbolically eat his flesh and drink his blood.
Two hours later, two shovel-nosed sharks approach. When he sees them, Santiago makes a noise that the narrator describes as a sound a man might make as he felt a "nail go through his hands and into the wood."
Nails were driven through Christ's hands when he was crucified. Here the sound marks both the death of Santiago's hope and his continued insistence on enduring pain.
Santiago kills the sharks using a knife that he's lashed to an oar, but not before the sharks have eaten a quarter of the marlin. He feels no pride in killing the shovel-nosed sharks, which he considers dirty scavengers. The marlin is now drained of blood and completely silver in color. Santiago wishes that he had not killed the marlin, and apologizes to the marlin for having gone out so far from land. He can't bear to look at the marlin's body, only half of which remains.
The sharks do not struggle with worthy opponents. They eat the dead remains of them. Drained of blood, the marlin loses its regal purple color and becomes a more deathly silver. Once again, doubts and regrets overwhelm Santiago.
A lone shovel-nose shark attacks. Santiago kills it with his knife, but loses the knife in the process. Two more sharks attack just before sunset. Santiago fights them off with the club he uses to kill bait fish. Exhausted and sore, he dares to dream that he might make it back with the half of the marlin that remains, and he believes that when darkness falls he will see the glow of Havana. He wonders if Manolin has been worried about him.
Santiago's ordeal becomes more difficult as more sharks come and he loses his weapons. At first he turns to hope to save him—the hope that he might make it back to see Havana. Then he uses Manolin's concern for him to help fuel his determination to get back to land.
When it finally gets dark, however, Santiago can't see Havana. He tells God he still owes him many prayers that he will say when he's not too tired, and he wonders if he "violated" his luck when he went too far out to sea. He again apologizes to the marlin for killing it, and promises to fight off the sharks even if it kills him. Around 10 pm, he sees the glow of the harbor.
Even with his hope of seeing Havana dashed, Santiago prays to God. He does not blame or demand anything of God, and does not give in to hopelessness. Instead he promises to fight despite certain failure.
Around midnight, a pack of sharks attacks the skiff. Santiago uses all his strength to fight them off with his oar and club, and finally, when those have been lost, he breaks off the tiller of his skiff and uses that to club the sharks. But by the time he kills or drives off all the sharks, no meat remains on the marlin.
Santiago can't possibly defeat the sharks, yet he does not surrender the marlin to them—he faces the sharks. This mirrors Christ, who redeemed mankind not by avoiding the cross but by suffering through it.
Santiago spits blood into the water and tells the sharks to dream that they ate a man. He checks his skiff, and sees that only the rudder is damaged, and can be fixed. He sails toward the harbor, thinking that the sea contains both enemies and friends. Utterly exhausted, he wonders for a moment what it was that defeated him. He decides that nothing beat him. He just went out too far.
Santiago's own blood mixes with the water, and by extension with the marlin's blood. He realizes that he pushed himself to the limits of endurance, and though success was impossible, he never gave up the struggle.
It is still dark when Santiago sails into the harbor. The lights on the Terrace are out, and he knows everyone is in bed. As he steps out onto the rocks, he looks at his boat and sees the giant white skeletal tail of the marlin lit by the reflection from the streetlight.
Santiago removes the mast of his skiff and wraps the sail around it. He rests the mast on his shoulders and drags it back up to his shack. It is so heavy that he is forced to stop and rest several times. When he reaches his home, he falls asleep on his bed facedown with his arms out straight and the palms of his hands up.