You’re staring at the map in Horizon Forbidden West. There it is. The Isle of Spires. It sits way out west, draped in the fog of a sunken San Francisco, looking like a jagged tooth sticking out of the Pacific. Honestly, it’s one of the most atmospheric spots in the entire game, but the Isle of Spires Relic Ruins is a massive headache if you don't know the specific internal logic the developers at Guerrilla Games were using when they built it.
Most players roll up to this ruin thinking it’ll be a quick ten-minute climbing puzzle. It’s not. It’s a multi-stage environmental riddle that requires a battery, an elevator, a code you have to find in two separate pieces, and a decent amount of patience.
If you've played the earlier ruins like the Daunt or No Man’s Land, you might feel overconfident. Don’t. This one is different because it’s vertical. Really vertical. You aren’t just pushing crates around a flat floor; you’re navigating the skeleton of an ancient skyscraper while the ocean breeze whistles through the rusted rebar.
Why the Isle of Spires is a Different Beast
Let’s be real for a second. The level design here is genius, but it’s also kind of mean. You have to use almost every tool in Aloy’s kit. Pullcaster? Check. Igniter? Check. Diving Mask? Absolutely.
The ruin is located on the southern part of the island. You’ll see the icon on your map, but getting inside isn’t as simple as walking through the front door. You’re going to be doing a lot of "Where do I go now?" spinning in circles. The main goal, as always, is to secure the Ornament—one of those weird holographic baubles that Stemmur back in Hidden Ember loves so much. But the path to it is blocked by a massive locked door that requires a six-digit code.
Finding that code is where most people get stuck. It’s not written on a single datapoint. Instead, it’s split. You find half on one floor and the other half somewhere else entirely. It's a classic "show, don't tell" moment that forces you to actually read the environment rather than just following a waypoint blindly.
Starting the Climb: The Battery Problem
First things first. You need to get power to the elevator.
When you arrive, you’ll find a battery charger, but the battery itself is missing. Or rather, it’s dead. This is where the Isle of Spires Relic Ruins starts to feel like a logic puzzle from an old Resident Evil game. You have to locate the energy cell, but once you pull it out of its socket, it starts losing charge.
You can’t just stroll around with it.
Basically, you have to find a way to get that battery from point A to point B before it runs dry. This involves a bit of platforming and some clever use of the Pullcaster to create shortcuts. If you’re too slow, the battery dies, and you have to go back and recharge it. It’s frustrating. It’s tense. But it’s also satisfying when you finally slam that glowing green cell into the slot and hear the elevator hum to life.
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Cracking the Isle of Spires Code
Once you have the elevator working, you can reach the upper floors. This is where the hunt for the code begins.
- The first part of the code is 21. You’ll find this on a datapoint titled "2nd Floor Survey." It mentions the floor number being part of the security access.
- The second part of the code is 09. You’ll find this on the "9th Floor Survey" datapoint.
- The final part? It’s 10.
Put it all together and you get 210910.
Why that specific number? Within the lore of Horizon Forbidden West, it refers to the date September 21, 2010. This was a significant date for the "Ancient Ones" who lived in this building. It’s a nice touch of world-building that rewards players who actually bother to read the text files instead of just skipping through the dialogue.
If you try to enter the code and it doesn’t work, double-check that you aren't standing at the wrong terminal. There’s a lot of tech clutter in these ruins that looks like it should be interactable but isn’t.
The Diving Mask is Non-Negotiable
You cannot finish the Isle of Spires Relic Ruins without the Diving Mask. Period.
If you’re trying to do this early in the game, stop. Go finish the "Sea of Sands" main quest first. You need the ability to breathe underwater indefinitely because a significant portion of this ruin is submerged. You’ll be swimming through flooded hallways, dodging submerged debris, and looking for a specific vent that leads to the final area.
Without the mask, Aloy will drown before you even find the right turn. It’s a hard gate. The game doesn’t explicitly tell you "don't do this yet," but the water level is a pretty clear hint.
Once you’re underwater, look for the yellow-painted edges. Horizon uses yellow as a universal signifier for "climb here" or "interact here." In the murky water of the Isle of Spires, these yellow accents are your best friend. Follow them to a submerged office area where you’ll find the final key module needed to unlock the main door.
Navigating the Final Stretch
After you’ve got the battery charged, the elevator running, the code in your head, and the key module in your pocket, you’re almost there.
Head back to the locked door on the main floor. Plug in the key, punch in 210910, and the door will hiss open. Inside, you’ll find the "Golden Toucans" Ornament.
Picking up the Ornament technically "completes" the ruin on your map, but don't just fast travel away immediately. Take a second to look around. There’s usually some high-tier loot tucked away in the corners of these ruins—Ancient Supply Boxes and sometimes even a few pieces of Greenshine. Given how rare Greenshine becomes in the late game for weapon upgrades, it’s worth the extra two minutes of poking around the rusted desks.
Common Mistakes to Avoid
- Dropping the battery in the water. If you drop the energy cell into deep water, it resets. You’ll have to go back to the charger. Be careful with your jumps.
- Forgetting the Pullcaster. There are several walls in here that look solid but can be ripped down. If you’re stuck, scan with your Focus. If a wall glows orange, rip it.
- Ignoring the map height. The Isle of Spires is very vertical. Sometimes the thing you’re looking for isn’t "over there," it’s "ten feet above you." Use the elevator to check every floor thoroughly.
- Skipping the datapoints. As mentioned, the code isn't just handed to you. If you don't scan the purple icons (datapoints), you’ll be guessing numbers for hours.
Actionable Steps for Success
To make this as painless as possible, follow this exact workflow when you arrive at the Isle of Spires:
- Ensure you have the Diving Mask. If you don't have it, leave and come back after the Vegas mission.
- Locate the battery charger and the cell. Don't pull the cell until you've mapped out your path to the elevator.
- Scan every purple datapoint. You need the clues for the code fragments (21, 09, and 10).
- Use the Focus (R3) constantly. The Isle of Spires is visually cluttered. The Focus pulse will highlight the yellow handholds and the crate you need to move.
- Combine the fragments. The door code is 210910.
- Deliver the Ornament. Take it back to Stemmur in Hidden Ember (Las Vegas) to change the skybox lighting. It’s a purely cosmetic reward, but it makes the desert look incredible at night.
The Isle of Spires is a testament to why Horizon Forbidden West is such a step up from Zero Dawn in terms of puzzle complexity. It’s not just about killing machines; it’s about understanding the space. Once you wrap your head around the verticality and the battery timing, it becomes one of the most rewarding "Aha!" moments in the game.