Adaptations are an important part of Subnautica 2. They allow you to access certain areas or unlock certain features. As of early access, there are 4 in the game to be found, 2 of which are very easy to find, and 2 are a bit harder.
Let's start with the easier ones!
Pressure Tolerance Adaptation
The pressure tolerance adaptation is the only one that cannot be missed, literally. The game won't let you exit the introduction area without it.
Digestion Adaptation
The digestive adaptation is still fairly easy to find, and allows you to eat the fish of the ocean without dying from it.
This Angel Comb is found about 180 meters North of where your life pod dropped.
Heat Tolerance Adaptation
The heat tolerance adaptation is a bit trickier, not only because it's a bit hidden, but there is also a small quest chain involved to unlock the Angel Comb.
First, to find the Angel Comb: Head about 200 meters west-southwest, and you will find a hill with a lot of entrances, it's under there.
As you can see in the picture above, the Angel Comb is a bit unwell. That's because it's infected, and our job is to cleanse it.
To do this, you first need to unlock the Sonic Resonator to shoot the infected spots.
Now, to do this, follow the tendrils spanning from the Angel Comb, and eventually, you will find a lot of infected spots, like in the picture below.
You want to shoot them in the near area until you get the message that none are left. You do this in 2 distinct areas. Afterwards, these will also appear near the Angel Comb itself, after which the chamber is unveiled for the adaptation.
Axum Vision Adaptation
This adaptation is much later in the game and is needed once you access the Alien Base.
It's needed to progress the story eventually.
The Alien Base itself is about 1800 meters east of the lifepod.
Well past this base, you will find the Angel Comb very deep underwater, so it is recommended that you bring the Tadpole for traveling. If you have trouble unlocking it, we have a Guide on that process.
Once you get down, you will notice tendrils again, which you need to follow, only this time you cannot use the Sonic Resonator because the Boom Clankers close when you approach them. For this job, you need the Feedback Resonator, the upgrade from the Sonic Resonator.
Once you have done 3 of these puzzles, you will need to do the same around the Angel Comb again, after which it will open up to give you the Adaptation.