"After weeks without human contact, it is normal to experience psychological discomfort. Research indicates symptoms may be partly alleviated by adopting a pet, or anthropomorphizing an inanimate object."
"It is normal when first piloting a Prawn suit to feel a sense of limitless power. Prawn operators receive weeks of training to counteract this phenomenon. You will have to make do with self-discipline."
"Congratulations, survivor: you have exceeded your weekly exercise quotient by 500%. Data indicates that swimming was your favorite activity. Be sure to vary your routine for uniform muscle development."
"This device appears to be configured to respond to concentrations of infected specimens. It may be possible to use it to locate the source of the contagion."
Hint from Gun to Lost River Base
"Scans of available alien data indicate the presence of a second facility elsewhere on the planet. Evidence suggests it is located 800m below sea level, approximately 1km south-west of this installation. Information recorded to data bank."
"Translating local alien broadcast... WARNING: Vaccine development program terminated. Emperor egg hatching project terminated. Live specimens terminated. Evacuate immediately."
"Unlike other alien facilities, scans indicate this location supports a diverse and healthy ecosystem. Explanation unclear at this time."
"The creatures' symptoms are being alleviated by the clouds of stomach enzyme being emitted by the leviathan. Scans indicate the enzyme is too unstable to act as a permanent vaccine."
"Detecting unusually passive behavioral patterns in nearby predators. Reason unknown."
"Environment scans indicate the water here is rich with a rare, plankton-like lifeform which depends on the organic detritus produced by the ecosystem around it."
"The plant life in this area is growing outside its normal conditions. Other lifeforms fertilizing and pruning the vegetation may be offsetting this environmental deficit."
"PDA: Picking up orbital transponder signature of trading vessel Sunbeam. Vessel is approaching planet surface and initiating surface scanning procedures. Detecting massive power surge from anomalous contact. Energy discharge detected. Vessel signature lost."
"PDA: Attention - Patching in a local broadcast from the Sunbeam.
I don't believe it, there's someone down there!
Aurora survivor, we have your PDA signature! I don't know how you walked away from that wreck, let alone survived since then, but we'll be happy to bring you onboard and hightail back to federation space.###-2000
Stand back, we're approaching the landing site now. Breaking atmosphere in 5... 4... 3...###2000
What is that? No the RED spike.###2000
From the planet?!
Due to the fact the AI at the beginning used to say "In the late 22nd century...", Subnautica is believed to take place between 2145-2199, explaining the high-tech items in-game. This message can be played below.
There are different voices speaking in certain dialogue, the voices change depending on where the player is. ex: The Standard female voice is there most of the game, but in a Seabase, Seamoth, Prawn Suit, and Cyclops the voices change. This may be due to the fact the player fabricates computer chips for all of these things, so it is possible computer chips contain AI's.
However, this may not be true, due to the fact that many other items are used with computer chips but they do not have their own AI.
Obraxis Prime is a reference to one of the Subnautica developers, Scott "Obraxis" MacDonald.
"You've been down too long in the midnight sea.", was a reference to the song Holy Diver by the US heavy metal band DIO.