But Jonah rose up to flee unto Tarshish from the presence of the LORD, and went down to Joppa; and he found a ship going to Tarshish: so he paid its fare, and went down into it, to go with them unto Tarshish from the presence of the LORD.
All Commentaries on Jonah 1:3 Go To Jonah 1
Haimo of Auxerre
In Hebrew, however, they speak generally of the sea as "Tharsis." Therefore, the prophet did not wish to flee to any particular place, but he embarked upon a ship which could take him anywhere, so long as he could hurry, not caring where chance led him.