Terraria separates identity from environment: player characters live in .plr files and worlds live in .wld files. That makes a complete backup a two-part job. Copy both directories, including .bak companions, before editing or moving systems. Steam can independently move individual characters and worlds to cloud storage, so an apparently missing local file may have a counterpart under Steam userdata. SaveEditor.com keeps those locations distinct instead of presenting one universal Terraria save path.
Prepare the source PC
On the source system, identify the actual Terraria save root: Windows: %USERPROFILE%DocumentsMy GamesTerraria
Steam cloud copies may appear under <Steam-folder>userdata<user-id>105600remoteplayers and worlds | macOS: $HOME/Library/Application Support/Terraria/ | Linux / Steam Play: $XDG_DATA_HOME/Terraria/ (normally ~/.local/share/Terraria/). The expected file/folder pattern is Players*.plr
Worlds*.wld
*.bak. Close the game, let the active launcher finish writing and synchronizing, then make a complete offline copy rather than transferring a file that may still be open.
Preserve storefront and profile identity
Documented storefronts: Steam, GOG Galaxy. Steam can keep cloud-designated player/world files under its userdata remote tree. The normal local Terraria directory still separates Players and Worlds. A transfer between two PCs is simplest when both systems use the same storefront/account/profile context. If the destination uses a different store or container, treat that as a migration problem rather than an ordinary restore.
Move the complete save boundary
Back up both Players and Worlds plus their .bak files. If a character and world belong together, keep them in the same dated archive even though they are separate files. Put the copied data on the destination only after confirming the destination save path. If the game creates a new empty save first, keep that new folder as another backup so you can compare structures and revert.
Handle cloud sync deliberately
Steam Cloud and GOG Galaxy are documented. On Steam, cloud movement is enabled per character/world rather than being assumed for every local file. Decide whether the local transferred copy or cloud copy should be authoritative before launching the game. If possible, preserve both. After the transferred save loads correctly, make a fresh in-game save and let the launcher synchronize normally.
Check compatibility before blaming the transfer
Characters and worlds are separate files: .plr for players and .wld for worlds. Local .bak companions can provide rollback material. Multiplayer characters and worlds should therefore be backed up as separate sets. Compatibility note: A world file and a player file have different structures and cannot replace one another. Cloud status can also differ per file. If the destination does not see the transferred progress, If a character or world is missing, check both the local directory and Steam remote location. Before using a .bak copy, preserve the current .plr/.wld and the backup so the recovery remains reversible. Verify game edition/version, store, profile IDs, redirected folders, and mod/DLC dependencies before editing the save itself.
Verification context: Windows/macOS/Linux locations, .plr/.wld patterns, Steam remote paths, and per-item Steam cloud behavior were reviewed against current PCGamingWiki coverage.