Ending guide · Final hand-in
How to Return to the Mainland & Finish the Game
The final boss is down—but the story is not complete until you deliver its Fin, take the military boat, and trigger the credits.
Quick answer
Give the Whale Fin to the Scientist and start the RHIB
After defeating the Mutated Bowhead Whale, collect its Whale Fin and return to the yellow-hazmat Scientist. Finish the hand-in to receive the RHIB keys. Find the military RHIB near the final-area camp, interact with the correct boat, and start it. The RHIB trip triggers the ending credits and the “We are so back” completion achievement.
01 · Requirements
Defeat the Mutated Bowhead Whale first
The return route only becomes available after the Volcano experiment and final boss are complete. If the boss is still active—or if you only defeated the regular Bowhead Whale—you are not at the ending hand-in yet.
Final bossHow to Beat Mutated Bowhead Whale02 · Final trophy
Pick up the Whale Fin
Collect the named quest drop after the lava-themed Whale dies. Current guides refer to it as the Whale Fin or final Whale tail. Keep the distinctive progression item rather than ordinary meat or the earlier regular Whale body.
03 · Final hand-in
Return the Fin to the Scientist
- 1
Return to the military camp
Carry the Whale Fin back from the Volcano encounter to the yellow-hazmat Scientist.
- 2
Complete the full dialogue
Hand over the Fin and continue the interaction until the quest reward appears.
- 3
Take the RHIB keys
These are endgame military-boat keys, separate from the ordinary boat keys earned near the start of the game.
Once the keys are in your possession, the Scientist chain is complete and the final boat can be started.
04 · Final vehicle
Use the military RHIB—not the wooden travel boat
Find the distinct military RHIB associated with the final area. The regular wooden boat used between islands does not trigger the ending. Approach the RHIB after receiving its keys and use the interaction prompt to start it.
Confirm that the RHIB or military-boat keys were actually awarded after the Scientist dialogue.
Look for the military-style RHIB near the endgame area rather than returning to your ordinary island boat.
Board or approach the RHIB and complete the interaction that starts the return trip.
The ending is confirmed by the return sequence and credits—not merely by owning the keys.
05 · Completion check
How you know the game is finished
The RHIB launch begins the trip toward the Mainland and rolls the endgame credits. The “We are so back” achievement is the clearest completion signal for the standard story route.
06 · Troubleshooting
Why the ending is not triggering
Make sure the final Whale Fin was collected and handed to the yellow-hazmat Scientist—not left at the boss arena.
Confirm that you brought the mutated final boss drop, not the earlier Bowhead Whale carcass.
Use the military RHIB associated with the final camp. The ordinary wooden travel boat is not the ending vehicle.
Owning the keys is not enough. Complete the RHIB start interaction and wait for the return sequence.
07 · After the story
Continue with achievements and collection
Current completion guides report that you can continue on the same save after the credits with your purchases and upgrades intact. This is the best time to clean up remaining Fishipedia entries, Drip creatures, weapon skins, trick-shot achievements, and challenge runs such as Handyman.
08 · Common questions
Ending FAQ
What do you do after defeating the final boss?
Collect the Whale Fin, return it to the Scientist, receive the RHIB keys, and start the military RHIB.
Does getting the RHIB keys finish the game?
Not by itself. You must interact with and start the RHIB to trigger the ending credits.
Can you keep playing after the ending?
Current guides report that the save remains available for post-game achievements, fish collection, upgrades, and skins.