This is the possible endings in Lost in Blue 3.
|Storyline||Eric, Claire||Medicine||Secret Base||None|
|Radio||All||Portable Radio, Broken Radio||Cape Area, then 1st Beach||None|
|Dinghy||Eric||Survive for ~42 days||Secret Base||None|
|Plane||Kumiko||Repair plane, Vaccine||Plane Crash Field||Lightning|
|HAM Radio||James||Restore power to the facility||Cherry Blossom Field||Heights|
|Raft||Eric, James||Build Raft, Sea Map||Treehouse Zone||None|
|Stay on the Island||All||Survive for 365 days||Anywhere||None|
The Dinghy ending must be done between 10 am and 3 pm, or else a unique ending will play where Eric is not rescued.
The 365 day ending is made easier by staying in the treehouse.
The Radio ending is likely one of the trickiest endings; as Sam or Kumiko, you must fish up the broken radio from the aboveground lake. You must stand on the center island and face upwards while fishing. If you are playing as Claire or James, you can get the broken radio by sending Sam or Kumiko out to gather food. The broken radio will have a frequency entered in already that can be viewed in the album. You must travel to the northern part of the Cape Area, dial in the frequency, and wait. The boat will arrive a week after you contact them. They arrive slightly faster if you tell them there is a bamboo grove on the island.