How to Host a Seaopolis: Submerged 2 Server
Seaopolis: Submerged 2 drops your whole world under water from the first tick — tiny islands, no dirt to punch, and a NeoForge 1.21.1 tech tree built entirely around the seabed instead of stone and ore veins. It's the sequel to the original Seaopolis, with a lot more content to work through, and it pairs well with groups who already cleared Seaopolis or Desertopolis and want a fresh biome-locked challenge. Getting it running cleanly just takes a few steps in the right order.
Start the server plan at 6 GB RAM — that's the floor Seaopolis: Submerged 2's own pack recommendation sets for NeoForge 1.21.1, and going lower just means longer chunk loads over all that open water.
Import the modpack directly from CoalHost's modpack list instead of uploading a client export — the server-side NeoForge files differ from what your launcher downloaded, and matching them by hand is where most ocean-pack installs go wrong.
Watch the console through the first boot and don't touch anything until it reaches the main menu line — ocean worldgen and the seabed-based tech mods both do heavy one-time setup work on launch, and a server that looks stuck is usually still generating structures below the waterline.
Only open the server to players after you've seen one full clean startup — since there's no traditional mining in this pack, a broken world seed or corrupted seabed chunk ruins the entire progression path for everyone, not just one player's mine.
Take a backup before importing an existing world, updating the NeoForge loader, or touching configs — losing a Seaopolis: Submerged 2 world means losing every bit of salvage and seabed progress your group has built up, and there's no dirt-level fallback to start over from.
Use a cleaner Seaopolis Submerged 2 path
CoalHost is built around modpack hosting, which makes Seaopolis Submerged 2 much less annoying to launch correctly.
Deploy Seaopolis Submerged 2 now →