For a long time, the answer was disappointing. While the game featured a robust single-player experience, the official multiplayer was restricted to two players (co-op). If you had a trio of friends looking to survive a plane crash in the Pacific, someone always had to sit on the sidelines.
: Even on high-end PCs, hosting more players can lead to significant frame rate drops and "laggy" physics, especially during raft travel. Mod Compatibility stranded deep 3 players mod
If you are looking to survive the Pacific with a larger group, here is the current state of the game and your best alternatives. 🛑 The Reality of Player Count Mods For a long time, the answer was disappointing