Set up a Seaopolis server

Seaopolis is an ocean-based survival and questing modpack for Minecraft 1.16.5 on Forge, by benbenlaw. Its CurseForge page describes a fully customised world with its own mobs and structures, where you start inside a sphere in the ocean and have to survive and build from there. The page also says the pack is in beta, so expect bugs and changes. You install the server from the Modpacks tab, using the pack's own server zip.

Checked against Seaopolis 16.1 on Forge 36.2.42 and Minecraft 1.16.5, October 2026.

What the pack needs

• Minecraft 1.16.5 with Forge 36.2.42. The server pack's variables.txt names both, and it ships no server jar, so the panel installs that Forge build for you. For Minecraft 1.16.5 the panel runs Java 8 on its own.
• Memory. The pack page calls a 4 GB plan perfect for it, and the server pack's variables.txt sets -Xmx4G. Your plan sets the RAM, so see how much RAM a Minecraft server needs and the Minecraft plans.
• Disk space. The server zip is about 181 MB and unpacks to about 217 MB, and the Forge install adds its libraries. The zip sits on your plan's disk while it unpacks, so keep room for both.
• The same pack version for players. This guide installs 16.1, released on 11 September 2026. Its changelog reads "Fixed infested leaves not dropping anything". Players need 16.1 in the CurseForge app.

Install the server files

Installing a modpack reinstalls the server and replaces the current world, so use a new server or one you can wipe.

1. Open Backups under Essentials and press Create backup if the server holds anything you want to keep.
2. Open Modpacks under Content in the left rail.
3. Press the CurseForge source button, then search for Seaopolis. Four packs by benbenlaw appear, and the original is the one that names Forge and Minecraft 1.16.5.
4. Press Install on Seaopolis. The popup says it reinstalls your server and names Forge and Minecraft 1.16.5.
5. Leave Take a backup first ticked. Tick Start the server when it's ready if you want the server to start itself, and tick I agree to the Minecraft EULA if the popup shows it.
6. Press and hold Hold to Install and reinstall until it fills, then watch the Console tab until the install log reports Pack installed.

First start

Press Start on the Console tab. The server pack carries no eula.txt, so unless you accepted the EULA in the install popup or earlier on this server, the panel opens Accept the Minecraft EULA first. The server is up when the console prints a line containing For help, type. Your address is in the left rail under Server address, and Connect to your server for the first time covers adding it in Minecraft.

The pack ships its own server.properties, and it sets level-type to skyblockbuilder:custom_skyblock. That is a world type from the Skyblock Builder mod. The World type list in Config Editor does not offer it, so leave World type alone and let the first start build the world. The same file turns on allow-flight and leaves spawn-protection at 16 blocks, which is Spawn protection (blocks) in the World section.

The server pack holds 174 mod jars, with FTB Quests and Skyblock Builder among them.

Other Seaopolis packs

benbenlaw also publishes Seaopolis 2 (Forge, Minecraft 1.19.2), Seaopolis: Submerged (Forge, 1.20.1) and Seaopolis Submerged 2 (NeoForge, 1.21.1). They are separate packs with their own pages. Search for the name you want, and players need the matching pack.

Common problems

• A player cannot join. They need Seaopolis 16.1 on Minecraft 1.16.5 with Forge.
• The server lags or runs out of memory. Watch the RAM card on the Console tab and the TPS reading in the left rail, lower View distance (chunks) in Config Editor under Performance, and move to a bigger plan if the RAM card stays full. Why is my server lagging has more.
• The install stops while unpacking. Your plan's disk may be too small. Check Disk Analyser, clear space and install again. Server out of disk space shows how.
• The server crashes at boot. Find and read a crash report shows how to name the mod at fault.