Shelldiver · Guides

Shelldiver 100% guide

Published by Chubuggles

A fast, fully offline incremental dive route to all 12 achievements, from the first 100 meters to the final hammock nap.

HelpfulSign in to mark this Helpful

  • ETA

    Estimated time, as the guide’s author estimates: 4-7 hours

  • Difficulty

    1/10, as the guide’s author rates it

Your Progress

12 achievements in this guide

Sign in with Xbox to see which of them you have already earned.

Game Page

Guide contents

Before You Start

Shelldiver on Xbox has 12 achievements worth 1,000 Gamerscore, all in the base game. One Store listing covers Xbox One, Xbox Series X|S, and PC through Smart Delivery and Play Anywhere, and they share one achievement list. The Steam version has a 13th meta achievement that does not exist on Xbox, so ignore it if you see it in a Steam guide.

  • Online: none. Every achievement is single-player and works offline.
  • Missables: none. Nothing locks you out, there is no point of no return before the end, and Prestige is a rank that opens new depths. It never resets your progress.
  • Unobtainable or bugged: as of 2026-10-11, no Xbox achievements are confirmed unobtainable or currently broken.
  • Playthroughs: one. There are no difficulty settings and no New Game+.
  • Save warning: the game has one save slot. Starting a New Game from the main menu wipes your progress, so never choose New Game once you've started.
  • Secret achievements: Hammock Sleep and Built to Dive are hidden on the list. Both are covered at the end of this guide.

The whole completion is one continuous loop:

  1. Board the submarine, pick a depth area, and dive.
  2. Bubble jellyfish until they are captured, and blast trash, crystals, and mushrooms for salvage.
  3. Surface before your oxygen runs out.
  4. Drop your jellyfish off with the shop vendor on the island. They sell over time, and the Shells collect in the chest next to the shop. Take your Shells from the chest. They don't go into your wallet on their own. On Xbox, stand between the shop and the chest and hold B to do both.
  5. Spend the Shells and salvage on the skill tree.

The shop keeps selling while you are underwater. Buying skills is what raises Prestige. Each new Prestige level opens the next depth area, 100 meters deeper, and you choose it from the submarine menu when you board. Don't sit on Shells. Spending them is how you progress.

The final skill and Hammock Sleep end the game's main loop. Save Hammock Sleep for last. Nothing else needs special ordering.

The Dive

First Dives

For your first dive, go into the lab and buy the starting Submarine upgrade. Board the submarine, choose Ocean Shallows and its 100m area, and deploy.

Learn the loop:

  • Fill your inventory with jellyfish.
  • Break anything your laser can hit.
  • Head up before oxygen runs low.

Early upgrades come quickly. Prioritize oxygen, capture speed, and inventory space. More oxygen means longer dives, and longer dives mean more jellyfish per trip.

100m Depth

This unlocks as soon as you reach 100 meters. Diving into the 100m area of Ocean Shallows on your first runs is all it takes.

200m to 400m

Keep buying upgrades as Shells come in. Every purchase raises Prestige, and each Prestige level opens the next depth step. Whenever a new one opens, select it from the submarine menu. Each new area adds resources the skill tree will ask for later. Break whatever is new as you pass it.

400m Depth

This unlocks when you reach 400 meters. Glacial Depths opens at 140 Prestige. Pick its 400m area from the submarine menu and dive. The submarine drops you straight into that area, so you don't need oxygen upgrades for this achievement.

500m to 600m

Your income starts to snowball here. Since patch 1.0.1, hovering over a skill node shows which salvage materials it needs. Use it to see which resources from this depth you should stock up on.

First 1M

This unlocks when you reach 1,000,000 Shells. Most players hit it around the 600m stage just by selling jellyfish normally.

Sources don't say whether the game counts Shells held or Shells earned. If you pass the threshold and it doesn't unlock, let your balance sit above 1,000,000 for a moment before you spend.

Make a Friend!

Other turtles appear on the home island as you progress. They are usually around by the time you have reached the 600m stage. Walk up to one on the island and press B to wave. The achievement unlocks on the wave. If a turtle doesn't respond, try a different one. If no turtle is there yet, keep diving and check the island each time you surface.

700m to 900m

Keep pushing depth and buying upgrades. Look at what the skill tree needs from earlier depths, because the final branches ask for older materials and you will have to dive back for them later.

700m Depth

This unlocks when you reach 700 meters. Swamp Waters opens at 300 Prestige. Pick its 700m area from the submarine menu and dive.

First 1B

This unlocks when you reach 1,000,000,000 Shells, usually around the 900m stage. The same balance precaution as First 1M applies.

1000m to 1100m

1000m Depth

This unlocks when you reach 1000 meters. Magma Abyss opens at 500 Prestige. Pick its 1000m area from the submarine menu and dive. This is the last depth achievement, but more depth steps open after it, and the final skills need them.

First 1T

This unlocks when you reach 1,000,000,000,000 Shells, usually around the 1100m stage.

The Alchemy Station

Several late skills cost life vials, and you make them at the Alchemy Station on the island. The station is a skill-tree upgrade of its own. Its node appears only after you unlock the Shellphone and keep buying up that branch. New nodes reveal themselves as you buy the ones before them, so a tree that looks finished may still have this branch hidden. Buy the station node as soon as it shows up.

The station has no interact prompt until you're holding 100T (100 trillion) Shells all at once. That's 100 times the First 1T threshold, so don't misread it. Once you pass First 1T, stop spending as you get close to 100T. Use the station when the prompt appears, then keep earning and converting until you can afford every life-vial node in the tree. One of them needs 100 vials on its own.

If the station won't work:

  • Make sure you actually bought the station node, not just a node near it.
  • Make sure you're holding the full 100T. You can't add the Shells a bit at a time.
  • If both are true and there's still no prompt, quit to the main menu, reload, and do one more dive. This is a reported fix, not a confirmed one.

1200m and the Endgame Skills

From 1200m onward, prioritize the two combo skills that make the endgame quick:

  • Biovalue Multiplication captures a stack of jellyfish with every catch. It opens at the 1200m stage.
  • Shellslot Capacity greatly raises how many jellyfish each inventory slot holds. It costs life vials from the Alchemy Station, and players usually get it a little later, around First 1Q.

Buy each one as soon as it's available. Check the hover tooltip for the exact numbers. Other late nodes cost life vials from the Alchemy Station too. Some need materials from earlier areas:

  • Scraps come from Ocean Shallows.
  • Crystals come from Glacial Depths.
  • Mushrooms come from Swamp Waters.

Hover over each locked node to see exactly what it needs, then go back to that area for it.

Ultra Special Rainbow Jellyfish

This unlocks when you capture a rainbow jellyfish. Rainbows spawn on their own fairly often, so you don't need to hunt one in a fixed spot. They become noticeably more common as you buy skills, and the Biovalue Increase X skill specifically raises the chance. Most players catch one during late-game dives without trying. Keep diving and capturing normally. When you see a rainbow-colored jellyfish, bubble it until it is captured.

First 1Q

This unlocks when you reach 1,000,000,000,000,000 Shells. With the combo skills bought, it arrives quickly in the late game. The final skill costs 10 quadrillion Shells, so you will pass this threshold on the way to it anyway.

Finishing the Tree

The Center Skill

Built to Dive

This unlocks when every skill in the tree is at max level. The last skill sits in the center, where all the branches meet, and it opens only after everything else is bought. It costs 10 quadrillion Shells.

If the center node won't open, a node somewhere is still not maxed. Scan the tree for anything unfilled, hover over it to see what it needs, and dive back for the material. The life-vial nodes are the ones players most often leave behind. If you're short on vials, convert another 100T at the Alchemy Station.

Your Prestige is the quickest check. Sitting at 799/800 Prestige is normal and doesn't mean anything is broken. The last point comes from the center skill itself. Once every branch is done, buy the center node for 10 quadrillion Shells to reach 800/800. If your Prestige is below 799, some node outside the center is still unfinished.

After the center skill, the hammock plays the game's ending. Have the other 11 achievements done before you lie down. With nothing missable in Shelldiver, the only thing left after this should be the hammock.

Rest at Last

Hammock Sleep

After buying the center skill, go to the hammock on the left side of the island. Repair it if the game prompts you to, then lie down in it. The achievement unlocks as the sleep and ending sequence plays. If it doesn't unlock, make sure Built to Dive has unlocked, then go back to the hammock.

Something broken or updated?

0 update requests

Sign in to request an update