Subnautica 2 Creature Scanning Guide: Codex Completion & DNA Samples
How to scan every creature in Subnautica 2 for codex completion and biomod unlocks. Scanner crafting, Bioscanner upgrade location, and DNA modification system explained.
Scanning Is the Game
Scanning in Subnautica 2 does more than fill out a database. Every creature scan feeds directly into the DNA modification system, unlocking biomods that permanently upgrade your character. Miss a biome’s creatures and you miss that biome’s upgrades. There’s no other way to get them.
This guide covers how to build your Scanner, where to find the Bioscanner upgrade, which creatures unlock which biomods, and the most efficient route to scan everything.
Building the Scanner
The Scanner is one of the first tools you should craft. Without it, you can’t unlock blueprints or begin building your biomod tree.
Scanner Recipe (Fabricator):
- 2 Titanium
- 2 Quartz
- 1 Basic Battery
Where to get materials:
- Titanium — Rock formations on the ocean floor near the surface. Everywhere.
- Quartz — Inside large orange coral formations on the ocean floor. They glow faintly at night.
- Basic Battery — Craft at the Fabricator with 2 Copper + 1 Acidic Raion Pouch. Copper is in caves beneath the Lifepod. Acidic Raion is in the cave 30 meters east.
You can have a Scanner within the first 15 minutes if you head straight for the cave under the Lifepod, grab Copper and Acidic Raion, surface for Titanium and Quartz from nearby coral, and craft everything at the Fabricator.
How Scanning Works
Point the Scanner at any creature, plant, fragment, or alien artifact. Hold the scan button until the progress ring completes. A few things to know:
- Scans persist through death. Whatever you’ve scanned stays scanned permanently, even if you die during or immediately after the scan. This makes risky scans almost always worth attempting.
- Blueprint fragments need multiple scans. Most equipment blueprints require 2-3 fragment scans before the recipe unlocks. Extra scans beyond the requirement give you bonus materials.
- You must be close. The Scanner has limited range. For aggressive creatures, this means getting dangerously near them. Distraction Flares help — throw one away from you and scan while the creature investigates.
- Scan everything once. Even if something looks decorative, scan it. Plants, rocks, alien structures, fragments — first scans often trigger recipe unlocks or codex entries you didn’t expect.
The Bioscanner Upgrade
The standard Scanner gives you codex entries and blueprint unlocks. The Bioscanner goes further — it collects DNA data that feeds the biomod modification system.
Where to Find the Bioscanner Blueprint
The blueprint is inside the Cicada Wreck, located in the second major biome where the water turns dark green. It’s roughly 1,800 meters east of the Lifepod, or about 600 meters southeast of the Alien Ruins Signal.
Look for the Blackbox Iso Signal wreckage. You’ll need a Repair Tool to access the interior. The degraded Bioscanner sits in a broken chamber at the bottom of the ship. Scan it to unlock the blueprint.
Bioscanner Recipe (Modification Station)
- 1 Scanner (your existing one)
- 2 Enameled Glass
- 3 Conduit Crystals
Enameled Glass requires Glass + Stalker Teeth or similar reagents at the Processor. Conduit Crystals are found near far-east alien power plants and observatories.
The Bioscanner is a direct upgrade — it replaces your Scanner, keeping all basic scanning function while adding DNA collection.
The Re-Scan Rule
Here’s the catch: the biomod tree only registers fauna and flora readings taken with the Bioscanner equipped. Any scan you made with the base Scanner has to be repeated with the Bioscanner to count toward biomod unlocks.
That means all those early creature scans? You need to redo them. Plan a re-scanning tour of the starting biomes once you build the Bioscanner.
The Bio Lab and DNA Modification
Bio Lab Location
The Bio Lab is inside the Welcome Center, about 87 meters southeast of your Lifepod at only 7 meters depth. To activate it, craft a Basic Battery and insert it into the empty power socket.
Biomod Slots
You get two types of biomod slots:
Active Biomods — Manually triggered abilities. Press Shift (PC) or L3 (controller) to activate. You can only equip one active biomod at a time.
Passive Biomods — Permanent background bonuses that run automatically. You start with one passive slot and can expand to six total through progression.
Default Biomods (No Scanning Required)
These are available from the start:
| Biomod | Type | Effect |
|---|---|---|
| Dash | Active | Quick burst of speed |
| Pathfinder | Active | Navigation assistance |
| Sea Skimmer | Passive | Improved surface swimming |
| Oxygen Control | Passive | Stretches air supply when you stop moving |
Oxygen Control is the most important early passive. Equip it immediately. It extends your oxygen every time you’re stationary, which translates to longer dives and safer exploration.
Creature Scan Unlocks
These biomods require scanning specific creatures with the Bioscanner:
Active Biomod Unlocks
| Biomod | Creatures to Scan | Effect |
|---|---|---|
| Sonic Echo | Collector Leviathan | Sonar-like pulse that reveals surroundings |
| Electric Discharge | Electric Geordie | Electrical attack that stuns nearby creatures |
| Chum Cloud | Toxic Sponge + Houndgar | Releases a cloud that attracts/repels fauna |
Passive Biomod Unlocks
| Biomod | Creatures to Scan | Effect |
|---|---|---|
| Bioluminescence | Sandspear + Electric Geordie | Your body emits light, replacing the need for a Flashlight in some situations |
| Camouflage | Bullethead | Reduces detection by predators |
| Threat Sense | Hoverthorn | Alerts you to nearby hostile creatures |
| Slow Metabolism | Nibbler Mango | Reduces food and water consumption |
Priority Scanning Order
Here’s the order I’d recommend scanning creatures based on usefulness and accessibility:
Phase 1: Starting Area (First Hour)
- Electric Geordie — Passive, safe to scan. Unlocks Electric Discharge and contributes to Bioluminescence.
- Geordie — Passive. Easy scan, fills codex.
- Water Slug — Passive, glows at night. Easy target.
- Halfmoon — Common passive fish. Scan one variant.
- Any flora and coral in the immediate area.
Phase 2: Expanded Shallows (Hours 2-4)
- Hoverthorn — Passive herbivore. Unlocks Threat Sense, which is extremely useful for exploring new biomes.
- Bullethead — Small and aggressive, but fast scan if you corner one. Unlocks Camouflage.
- Houndgar — Contributes to Chum Cloud (also need Toxic Sponge).
- Toxic Sponge — Flora, not fauna. Completes the Chum Cloud requirement.
Phase 3: After Bioscanner (Mid-Game)
- Re-scan all Phase 1 and 2 creatures with the Bioscanner equipped.
- Sandspear — Aggressive, dangerous. Completes the Bioluminescence biomod. Use Distraction Flares to divert its attention before scanning.
- Nibbler Mango — Aggressive. Unlocks Slow Metabolism. Worth the risk.
- Collector Leviathan — The hardest scan in the game. You need to get close to a creature that kills you on contact. Distraction Flares and co-op help enormously. Unlocks Sonic Echo.
Tips for Scanning Dangerous Creatures
- Distraction Flares first. Throw a flare away from your position to redirect an aggressive creature before attempting to scan it. The scan takes several seconds — you cannot afford to be interrupted.
- Scans survive death. If you’re at 90% scan progress and die, that progress is saved. Swim back and finish the last 10%.
- Co-op scanning is easier. One player distracts, the other scans. This is the safest way to scan Leviathans.
- Night scanning is harder for visual identification but some creatures (Water Slugs, certain flora) glow and are easier to spot.
- Scan from vehicles when possible. Your Tadpole provides protection while you point the scanner through the cockpit.
- The Collector Leviathan scan is a rite of passage. Approach from behind while its attention is elsewhere, and start scanning immediately. Co-op or Distraction Flares make this far more manageable. Multiple attempts may be needed.
Codex Completion Checklist
The Early Access codex tracks scans across categories:
- Fauna — 51 creature archetypes
- Flora — 30+ plant types
- Fragments — 100+ blueprint fragments
- Alien Artifacts — Data terminals and structures
A complete fauna codex is currently impossible in a single biome. You need to visit every accessible area of the map to scan every species. The Void contains Shiver Leviathans that can be scanned, but the trip is extremely dangerous.
Focus on completing one biome’s scans before moving to the next. Systematic coverage beats random exploration every time.