Scholars disagree on this question, but the poem seems to indicate that the seafarer is ultimately searching for heaven. He does, however, pine for the open oceans in the same way Tennyson's "Ulysses" admits "you and I are old; / Old age hath yet his honour and his toil; / Death closes all: but something ere the end...." The seafarer has the same sentiment: 

And now my spirit twists
out of my breast,
my spirit
out in the waterways,
over the whale's path
it soars widely
through all the corners of the world --
it comes back to me
eager and unsated....

Both are old salts, aging adventurers, who believe that common people, landlubbers, are missing the only thing they themselves would call "living," "As tho' to breathe were life!" (Tennyson line 24). 

Only, while Ulysses wants only to sail and explore and have adventures until he dies, the seafarer turns his attention to otherworldly things. In contrast to the adventures with foreign peoples and fighting the seas that he misses, he says

Indeed hotter for me are
the joys of the Lord
than this dead life
fleeting on the land. 

Instead of testing his mettle against the seas and foreign peoples, he is turning his attention to fighting the "enmity of devils" to earn "the glory of eternal life." He observes that the people in charge of the world now are the weakest sorts of men while the truly noble grow old and die, hinting that his work--as a man who will fight for what's right and good--is cut out for him. He ends with the admonition to "ponder / where we have our homes"--our ultimate homes, he means, in heaven or hell--and think about how we will get there. 

The seafarer is searching for the good in the world, but ultimately he seeks a place with God and the Hosts in heaven when he dies.