The Old Man and the Sea uses a third person, omniscient narrator. This objective narrator never has an agenda or specific perspective. The third person in this novel describes things as they are. Therefore the narrator is quite reliable. In the first lines of the book, the reader gets some background information about the fisherman, the boy, and the other fishermen. The narrator describes what happens physically but the reader also receives insights into the minds of the characters. For example, the reader learns early on that some fisherman make fun of Santiago while others took pity on him but did not speak of it:
Others, of the older fishermen, looked at him and were sad. But they did not show it and they spoke politely about the current and the depths they had drifted their lines at and the steady good weather and of what they had seen.
There are times when the narrator shifts from describing Santiago as "he" and uses "I." This is not the narrator's speech or thought. It is Santiago's speech and thought. This does not detract from the narrator's objectivity or reliability. It is simply a shift from third person to first (Santiago's point of view):
It must be very strange in an airplane, he thought. I wonder what the sea looks like from that height? They should be able to see the fish well if they do not fly too high.
This is an interesting example of this shift from third person to first because Santiago describes a perspective that is a bird's eye view, a view from the sky. This is somewhat analogous to the third person narrator who can see from an objective point of view. The difference is that the narrator in this text can provide a character's thoughts as well.