How to Host The Ocean of Subnautica Server (Forge 1.20.1)

Start with at least 5 GB of RAM — that's the recommended floor for The Ocean of Subnautica's Forge 1.20.1 modlist, which covers the custom ocean generation, submersible mechanics, and alien sea life without starving the server from day one.

Import the modpack directly from its official package on CoalHost instead of guessing at a mod list from a client export — the underwater base-building and submersible crafting in The Ocean of Subnautica depend on a handful of tightly-paired mods that are easy to get out of sync by hand.

Watch the console through first boot until world generation finishes cleanly — this pack carves out a much larger and deeper ocean than vanilla, with custom biomes and trench structures, so give it time before assuming it's hung.

Only invite players once that first clean startup is confirmed — a crash mid-dive while someone is exploring a deep trench can cost them their submersible and everything they were carrying.

Take a backup before importing an existing world, updating the Forge modpack version, or changing configs — losing a world here means losing however many hours a group spent building out their underwater base network and upgrading toward the deeper, more dangerous depths. Unlike most ocean-adjacent survival packs, The Ocean of Subnautica is built specifically around that base-and-submersible progression, so there's no quick land-based fallback if the world is lost.