Verified for the August 2026 patch · updated Aug 20, 2026
Harbor (Large) Puzzle Guide — Green Card Route
Large Harbor needs a green keycard and 1 electric fuse. Reward: a blue keycard. Fuse and switch in the two-story building, then swipe the second-floor door.
Difficulty: easy · time on-site: 3–5 min · by RustLogic Staff
Bring exactly this
- Green card ×1
- Electric fuse ×1
Both Harbors run the same trade — one green card, one fuse, one blue card back — but the large Harbor wraps it in a bigger monument with better loot density and boat access.
Before you go
Green keycard + one electric fuse. No rads, no NPCs. If you’re coming by boat, the dock puts you close to the puzzle building.
The route
- Find the two-story building. It sits among the warehouses — look for the structure with interior stairs rather than the open storage sheds.
- Fuse in, switch on. Ground floor: place your fuse in the fuse box and flip the switch. The second-floor reader is now live.
- Upstairs, swipe green. Take the stairs, swipe the reader, and the door opens.
- Take the card. Inside: a crate and the blue keycard. Grab both.
After the run
Recycle your dock barrels before leaving, and check the pier — on current maps the Cargo Ship periodically docks at large Harbors, turning this sleepy card stop into a full loot event if your timing is right.
Harbor (Large) — quick answers
- What do I need for the Harbor puzzle?
- A green keycard and one electric fuse — same for both Harbor variants. No radiation protection needed.
- Which building is the Harbor puzzle in?
- At the large Harbor it's the two-story building: fuse and switch downstairs, green reader on the second floor.
- What's in the Harbor puzzle room?
- A blue keycard and a crate. Quick in, quick out — it's one of the fastest blue-card sources in the game.