Here is the full list of all 30 Beyond Blue achievements. It takes around 5-6 hours to unlock all of the achievements on Windows.
Complete the game
Complete Dive 8
Unlock all of the models in the Scan Model Viewer
Complete Dive 7
Complete Dive 6
Scan all of the octopuses in the game
Unlock every type of shark in the Scan Model Viewer
Complete Dive 5
Unlock every type of jelly in the Scan Model Viewer
Unlock the Giant Clam in the Scan Model Viewer
Complete Dive 4
Complete Dive 3
Complete Dive 2
Unlock every type of whale in the Scan Model Viewer
Change the music five times in your sub's music player
Choose a song in your sub's music player
Watch an Ocean Insight video
Complete Dive 1
Start your journey
Watch all of the Ocean Insight videos
Unlock everything for the White Tip Reef Shark
Unlock everything for the Bottlenose Dolphin
Unlock everything for the Ocean Sunfish
Scan everything in the game
Scan everything in all dives to the Atoll Region
Scan everything in the Open Ocean Region
Scan everything in the Seamount Region
Scan everything in the Brine Pool Region
Scan everything in the Vents Region
Scan everything in the Coastal Region