To unlock Submarine Parts, you have to finish mission “Death on the Sea”.
This mission is only available for Michael and appears when you buy a property marked on the map.
When you begin it, a boat for finding Submarine Parts will appear in docks.
Don’t worry, because this boats gives you diving equipment automatically.
This site is not associated with and/or endorsed by the Rockstar Games or Rockstar Games.
All logos and images are copyrighted by their respective owners.
