Two passages describe Zebulun in maritime terms and one does not, and the tension between them is one of the durable puzzles of the tribal geography.
Jacob's blessing says Zebulun shall dwell at the haven of the sea, shall be for a haven of ships, and his border shall be toward Sidon. Moses' blessing pairs him with Issachar and speaks of the two sucking the abundance of the seas and treasures hidden in the sand. But the boundary list in Joshua 19 traces a territory in lower Galilee, running between the Jezreel valley and the hills, that touches no coastline at all and comes nowhere near Sidon.
Several explanations have been offered and none has settled it. The blessings may record a claim, or an older distribution, or an economic reality in which the tribe worked the trade routes to the coast without holding the shore, since the road from the Mediterranean ports up into Galilee ran through its territory. The boundary lists may be later and more administrative than the poems, which are among the oldest material in the Hebrew Bible.
What the tribe demonstrably held is good ground on a crossroads: hill country and valley heads through which traffic between the coast and the inland routes had to pass, and which supported farming. The blessings and the boundaries agree on prosperity and disagree only about water. That the compilers preserved both, without harmonising them, is characteristic of how the tribal material was handled.