You will need a Roblox executor (like Hydrogen or Fluxus for Mobile, or Wave/Solara for PC).
It is best to execute the script once you are already at the Frozen Outpost in the Third Sea. Blox Fruits Auto Leviathan Keyless Script
In the Sea 3 "Frozen Outpost," players normally have to bribe the Spy NPC multiple times to track the Leviathan, which costs thousands of Fragments. Even then, finding the "Gates" in the Rough Sea (Danger Level 6) is time-consuming. You will need a Roblox executor (like Hydrogen