Answer:
The Roman fleet was dominant so Hannibal had to go overland.
Explanation:
the Carthaginians did not have a stronger navy than Rome. The First Punic War had effectively annihilated the Carthaginian fleet, and they were forced after the war to severely limit the size of their naval forces, which they did anyway under the influence of Hanno and other anti-war politicians who didn't want to risk another scrap with Rome. Related to that is the fact that Rome had seized Sicily, Sardinia, and Corsica after the war, so that any naval passage to Italy would've had some serious trouble getting through all those naval bases (the fact that the Carthaginians were later barely able to transport a few thousand cavalry and some elephants to Hannibal by sea, despite the panic that Rome was in, shows just how difficult it was for the Carthaginian fleet).
Bypassing Roman and allied land garrisons and Roman naval dominance, Hannibal managed to lead his Carthaginian army over the Alps and into Italy to take the war directly to the Roman Republic.
The Carthaginian general Hannibal led his army, including dozens of war elephants, on an epic march across the Pyrenees, through France, and over the Alps into Italy. For 15 years, Hannibal and his army moved across Italy, winning battle after battle which surprised Rome.
