Here is where you should avoid.

Don't go to the Dunes, a desert looking place with pillars. It spawns a Reaper Leviathan.
Don't go to the Aurora. It spawns a Reaper Leviathan.
Don't go to the Mountains, you can get trapped on the island too. It spawns a Reaper Leviathan.
Don't go to the Deep Grand Reef, which is the deep end. It spawns a Reaper Ghost Leviathan.

Here is where you should go.


Nowhere, just stay in the raft and talk to Mr. Tissue, Mr. Coin, and Mr. Potato Chip because it is not safe outside.

10/10 would not go to the Dunes again. Ever.

EDIT: Now with Nopesquids!

EDIT EDIT: Don't be surprised if you find you've filled your stillsuit with piss my scuba lads.

Don't go to the Active Lava Zone, which is the deeper deep end. It spawns a Sea Dragon Leviathan.
Don't go to the Lost River, where there is water underwater. It spawns a Ghost Leviathan.
Don't swim out of the game you fool, stay out of the void. It spawns many GIANT Ghost Leviathans that want you to stay in the Dunes, Aurora, Mountains, Deep Grand Reef, Active Lava Zone, and Lost River.