In “Apostrophe to the Ocean,” Lord Byron gives his most explicit answer to this question in the final stanza, where the speaker confesses that, as a boy, the ocean’s “breakers…were to me a delight,” and that any fear caused by the untameable nature of the sea was “a pleasing fear.” He adds that, “For as it was, I was a child of thee.” Lord Byron spent his formative years in Aberdeen, near the ocean, and it seems that his speaker had a similar youth; from this poem we can assume that the water was his chief source of play and sport.
Consider the first stanza of the poem, with its iconic line, “I love not Man the less, but Nature more.” This ties in well with the nostalgia of the final verse, and sets the tone for the rest of the poem. The speaker loves and, perhaps more importantly, respects the ocean, for man cannot conquer it. The speaker loves nature more than man, he states, and therefore loves beyond the rest the one element of nature with which man has resigned himself to an oft-compromised truce. In the second verse, Byron writes,
Man marks the earth with ruin – his control
Stops with the shore – upon the watery plain
The wrecks are all thy deed, nor doth remain
A shadow of man’s ravage, save his own.
Lord Byron continues in the third verse to emphasize this point by describing the effortlessness with which the ocean can destroy a man. No matter what man does upon its waves, the ocean is not a “field” and does not play by the same rules. The sea will always win, and the speaker revels in its noble, awesome constancy.
The ocean is hostile in its indifference to land and city, heaving and roiling and outlasting even the fairest of civilizations – the speaker lists them: “Assyria, Greece, Rome, Carthage – what are they?...their decay has dried up realms to deserts: not so thou/Unchangeable save to thy wild waves play.” So the speaker loves the ocean as well because it is enduring; while time changes the earth and all living beings soon succumb to its caresses, the ocean remains as itself, and so as it has always been. The speaker muses that “Such as creation’s dawn beheld, thou rollest now.” The sea represents stability in a changing world, and this indeed is something to be admired.
So, in this poem we see three main reasons the speaker loves the sea: he played in it as a child, and came to love its capricious ways and the excitement and uncertainty its waves espoused; he, a lover of nature, is awed by its destructive capacities and the inability of man to exert his dominance over it; and he admires it for its longevity and unchanging nature in a world that has decayed and been reconstructed countless times over its history.