In Abzu there are 19 hidden shells. 3 per level (except chapter 5!) spaced throughout the primary environments and 1 at the very end within plain sight. A lot of these shells are pretty easy to stumble across, but some of them can be tricky. Thankfully, there are numerous mural painting walls (one in every level with shells) that help you track your progress. Usually these are towards the end of the level. To help with that (and to make it easier to get the sweet reward for collecting them all) I've scrapped this together.

Before we get started, I'd like to extend my gratitude towards some commenters for their assistance:
•Thank you Wiedźma Danaien for pointing out where the last shell in Chapter 3 is. Saved me some time!
•Thank you Blecco for pointing out that what I thought were the ancient nautilus (nautili?) are actually ammonites. Good eye! (Taking Wing points out that the ammonite is an extinct species while the nautilus survives to this day! Fascinating!)
•Thank you Viporion for pointing out that the last shell in Chapter 3 could do with some clarification. It is now updated and should be much more clear.
•Thank you {MK}DXFrost for pointing out that I did not state that their is a mural wall in every section. Clarification is always welcome!

Movement Tips
Word to the wise, make ample use of the boost in this game. For starters, it makes swimming and breaching much more enjoyable. Secondly, and importantly, it will help speed up your collection.

(Be advised, I'm using a controller, which I think makes the game much more fluid - har har)
So, the easiest way is to tap simply tap 'A'. This will give you a short term boost that doesn't really do much. If you hit 'A' again too soon, your diver will slow down.

For a large boost, hit 'A' and then immeaditely hit 'B' to perform a roll. This will cause your fins to glow gold and you'll have an incredible burst of speed when you exit your roll. This method, while quick, is not very easy to steer with.

The best method, I've found, is to time your boosts according to a rhythm. Initiate the first little boost and if you hit 'A' again you'll notice a larger boost. This will be accompanied by a much more pronounced dolphin swim. After this, time another 'A' hit just right and your fins will glow gold, giving you a huge boost. For an added kick, roll just as your fins turn gold. It will prolong the boost a bit.

Give it a try and get used to the rhythm. You'll get used to soon enough, and you can even string full boost chains together to continue swimming at peak speeds.

1st Shell
Make your way through past the grouper and into the area proper. Start swimming towards the first meditation statue.


Swim towards the ground and you'll notice an arch. Swim through and you'll find your first shell.


2nd Shell
Continue on until the Great White swims away from you. Continue through this alcove until the ground begins slopping upwards at the end.


Hang a left and you'll see the 2nd shell nestled on a rock on the floor.


3rd Shell
After you've restored the coral spire, swim through until your probe gets killed.


Swim down and left, and keep swimming until you hit the sea floor. Follow the rock spires until you reach the 3rd one, and check the left side. Shell number 3 will be waiting.

4th Shell
I absolutely love this level. No shells are in the first stream, so enjoy the ride. When you dump out into the first zone, the 4th shell will be perched up high on the rock spire.


5th Shell
Next shell is in the upcoming slipstream. It'll come up quick, so be ready. Cut away the coral and dive in.


This one is very easy to miss. I suggest ignoring the fish as they'll only serve to distract and obscure your vision. Keep your eye peeled, and when you see this ledge get ready. Your sonar (echo?) will hit it no problem, but it is quick.


6th Shell
Last shell of the level, and again it's in the gorge before the end gate. Start swimming down and keep to the left again.


This shell is in a rock outcropping fairly close to one of the coral reefs. Grab it and complete the level.

7th Shell
Upon entering the area proper, start swimming to your left towards the meditation statue for the area. You'll notice a coral reef, grab that if you haven't yet.



Swim into the pit and your shell will be at the bottom.


8th Shell
Continue through the doors and the small canyon. Eventually you'll encounter our old friend the Great White.

When he swims off, swim to your right behind the kelp. You'll see this shell being guarded by a fierce octopus.


9th Shell
After you restore the coral spire swim towards the gate that just opened and up, past the shark statues.


This shell is tucked behind a wall just above the gate, easy enough to find.

10th Shell
Swim with the whales until you reach the sea floor. Start swimming forward and stay away from the ground. The next shell is at the highest peak down here.


As you swim closer you'll notice the shell nestled amongst the bones of the dead. Claim your dread prize...


11th Shell
Activate the area door and release our old friend. Continue through the archway...


...and swim up and to the right. This shell gave me the most trouble out of all of them, and I felt ridiculous.


12th Shell
Descend into the abyss. They did a great job on this area. Even though I know I can't die, my heart always beats a little harder as I go deeper. Primal, I guess.


This one's easy, you should find it no problem. It's on a cliff coming off the rock wall opposite the entrance to the coral spire chamber.

(Note that Chapter 5 is the Machine Factory)


13th Shell
After entering the city, release the first chain. Surface, and you'll see a platform you can climb up onto with some stairs.


Climb them and walk the path. This one's easy.


The next shell is in the same area. From your vantage point, look out towards the right. You'll see the waterfall wall and a small platform jutting out from it.


Climb the platform and follow the path. A nice change of pace, this one's actually hidden pretty well!


After you open the gates and ride the current to the top, look out over the next area. You'll see a gazebo on a platform. That's where you're heading.


Climb the platform and claim your prize.

16th Shell
As soon as you breach, look to your right. You'll see a land outcropping with the shell resting nicely on top.


17th Shell
Both of the final shells for this level are in the very last area with the blue whales. So, when you breach this place you can hang either right or left.


For simplicity's sake, let's go right first. Swim along the rock wall and keep an eye on the surface. You'll see a small bit of land you'll have to jump up pretty high for. Grab the shell, only 2 more!


18th Shell
Now we go left. Swim along until you find a small chunk of ice floating in the sea. Climb on (or land it) and you'll see this shell laying before a polar bear. He won't bite, take it with no worries.

After you beat the machine, you'll dump out on top of it, your god powers freshly spent for the greater good. Swim around with your shark pal, enjoy the credits, and grab the last shell for the achievement.

Here's the cool bit. Once you have all 19 shells, swim to any of the murals that track your shell progress. You'll notice you can now interact with the wall. Intriguing...


And now the power of the Ammonite is yours to keep! Enjoy!


There's a problem with some people not being able to activate achievements. I have no idea what this is related to, but I do know of a work-around. Go to:
C:\Users\(profile name here)\AppData\Local\AbzuGame\Saved\SaveGame and delete the ABZU.sav file. This is a complete reset, so be aware you'll have to replay the entire game and unlock/collect everything again.

If you liked my guide, please rate it! Thanks for your time!