Quick answer: The third island is the Desert Island. Talk to the Tourist, bring back a creature that the game marks endangered and keep the Carrot he gives you. Prepare your ranged weapon before using the Carrot, defeat the Pufferfish and return the required trophy to receive the next progression information.
Story location order
How to reach Island 3
Island 3 follows the Giant Piranha route on Island 2. Complete the three-Leech quest, use the modified bait for the Piranha encounter and finish the boss hand-in before expecting the next island route to open.
If the Island 2 quest is stuck, use the three-Leech guide first.
Third Island checklist
| Objective | Action | Keep |
|---|---|---|
| Map the island | Talk to the Tourist and other available NPCs | Quest context |
| Grillmaster (optional) | Use a Standard Boss Lure for the Blue Shark | The Blue Shark for the side objective |
| Tourist request | Catch and inspect an endangered creature | The Carrot reward |
| Prepare | Buy ranged damage and enough ammunition | Cash for a retry |
| Pufferfish | Use the Carrot and kite around cover | The boss trophy / Fin |
| Progress | Return the required trophy to the Tourist | Next coordinates |
Optional: Blue Shark and the Grill
The Standard Boss Lure can summon the Blue Shark on Desert Island. This is a useful Grillmaster side route, but it is not the boss that unlocks Rocks Island. If money is limited, secure the Tourist's Carrot and the Pufferfish loadout first.
Open the Blue Shark encounter guide →
The endangered creature request
Use the current build's inspection information rather than memorising one species from an old video. The quest cares about the endangered status. Inspect catches before cooking or selling them and return one that the game explicitly labels endangered.
Optional: the Bing Bong catch
Bing Bong is a secret catch on the Desert Island. Buy the Coconut directly from the marked palm tree, use it with a Fishing Rod and prepare for a fast fight after the catch lands.
Follow the illustrated Bing Bong and Coconut route →
Prepare for the Pufferfish
Do not use the Carrot the moment you receive it. Check your ammunition, inventory space and escape route. The Pufferfish is safest when fought at range while circling the island's trees. Its later phase leaves purple poison, so old ground can become unsafe.
Read the complete Pufferfish boss strategy →
Why players get stuck here
- Selling an endangered catch before reading its status.
- Using the Carrot without a useful ranged weapon or enough ammunition.
- Killing the Pufferfish but bringing the wrong remains back to the Tourist.
- Leaving the island before the trophy hand-in completes.
- Following a launch-day species or damage claim that changed in a later patch.
Sources and verification
- Official Steam page — island, quest and boss progression loop.
- PC Gamer's Island 3 Pufferfish route — Tourist and endangered-creature quest.
- Destructoid complete walkthrough — Blue Shark side route and Pufferfish progression.