Sons of the Forest: How To Open The Arm Door

Whether you get scared or not, be brave enough to venture through the horrors to open the arm door located within!

Sons of The Forest is probably one of the most interesting games where players are made to pass through caves, solve puzzles, craft items, go traverse the lands to ge their hands on precious loot that can help them further progress in the game. Similarly to that, players might have quite a bit of difficulty trying to figure out how to open the Arm Door in Sons Of The Forest since it requires two essential items; maintenance key & golden armor.

Important: To open the arm door and complete one of the final missions in the game, players need to get the maintenance key and wear golden armor. 

Key Takeaways
  • The arm door is located deep within a underground building that is located on the opposite end of the island. 
  • The arm door is also referred to as the Golden Hand Seal Door; therefore, players need to know to note get mixed up between the terms. 
  • Players need 2 essential items before they can open the door, including golden armor as well as a maintenance key. 
  • In order to open the arm door, players need to be wearing the golden armor suit and align their arm with the marking on the arm door, and it opens up. 
  • To get the golden armor suit, players need to go into a cave, head over to the level 2 building, and put the suit is sat on top of a couch in the living room. 
  • The golden armor suit comes in handy to protect players during combat as it provides you with a full HP bar. 
  • The maintenance key is located inside a bunker underground, and it is placed on a table besides a 3D printer
  • The maintenance key can also come in handy to gain access to the katana in the game. 

How To Locate Arm Door 

First things first, one thing that players should know is that whenever they are playing the game, the Sons Of The Forest Arm Door is also referred to as the golden hand seal door; therefore, players should know not to confuse the two terms. 

  • Before players can even get started, they need a total of 2 essential items, which entails needing the golden armor suit as well as the maintenance key, without which players are not able to unlock or enter the armed door. 

Starting Out 

Way To Enter The Arm Door
Way To Enter The Arm Door (Image Credits Exputer)

From the start, players want to make their way over to the opposite side of the island, and they always have a GPS on hand which helps them guide on where they need to go. 

Nature Overtaken Entrance
Nature Overtaken Entrance (Image Credits Exputer)
  • From here, you want to encounter an entrance that is covered by nature and leads further deeper in. 
  • The indication for the correct place is the worker in the red suit that is leaning on the right side of the entrance and appears to be dead. 
Red Body By Entrance
Red Body By Entrance (Image Credits Exputer)
  • Come towards the green beacon on the opposite end of the island, and players can find the location by traversing around the snowy mountains and going to the opposite end. 
Maintenance Key Entrance
Maintenance Key Entrance (Image Credits Exputer)

When you head closer to the door, the door ends up being locked and requires the use of a maintenance key (covered later on how to attain it which opens the door. 

  • Head through the dark hallway, turn left and continue to move while being guided by the illuminated lights on the roof. 
  • Players can also take help from a torch if they feel like it’s way too dark inside. 
  • Make a right turn, and then continue down the stairs, and go towards a door which is located towards the left at the end of the stairs. 

Heading In The Door 

From here, you are inside a building that has been illuminated in the same way that the hallways were. 

One Of The Three Doors
One Of The Three Doors (Image Credits Exputer)
  • From here, keep heading straight, walking towards the edge, and continue heading past a total of 3 doors
  • Once you are out, make a left turn and head down the hallway until you appear infront of the yellow door. 
Yellow Door
Yellow Door (Image Credits Exputer)
  • Take a left from the door and run past the room, and make a left turn when heading out of the room with the yellow door. 

Heading Into The Cave

Black Ottoman
Black Ottoman (Image Credits Exputer)
  • Head past the wet floor sign in the hallway, and continue making your way toward the lobby. 
  • Run through the hallway and enter the penthouse, and head into a room by a black ottoman
Cave Leading To Arm Door
Cave Leading To Arm Door (Image Credits Exputer)
  • Go into the dismantled bathroom, and start heading into the cave. 

Stop when you encounter a lined door that happens to be the golden seal or the Sons Of The Forest Arm Door

How To Open Arm Door 

Lined Door
Lined Door (Image Credits Exputer)

Whenever you do encounter the door, players need to open it to go inside. 

  • The way that players can open the door is by getting close to it and interacting with it by pressing E, 
  • Players need to be wearing the golden suit whenever they approach the armed door. Otherwise, they aren’t able to unlock it. 
How To Open Arm Door
How To Open Arm Door (Image Credits Exputer)
  • All players need to do is use their arm, align it with the arm marking on the door, and slam their arm against it which ends up opening the door for them. 

Gold Armor Suit Location  

Moving on, now that players know how to locate and open the arm door in Sons of The Forest, the next thing that we will be taking a look at is how to locate the gold armor suit, which is a key essential to open the door. 

Opposite End Of Island
Opposite End Of Island (Image Credits Exputer)
  • The first thing that players want to do is to make their way toward the opposite end of the island, which is done by tracking the map, traveling and climbing the mountains, and tracking your way 
  • You want to move around the snowy mountains, which then further lead you toward the other end of the island. 
Entrance To Cave
Entrance To Cave (Image Credits Exputer)
  • After that, you want to locate a green beacon and locate a cave that is hidden extremely well between a tall mountain edge as well as two mountain cliffs that have a massive cut through the middle to make way for the entrance of the cave

Heading In The Cave 

Once you’re through the entrance of the cave, you want to start exploring it further and making your way down

Using Torch
Using Torch (Image Credits Exputer)
  • Use the help from your flashlight to light the way for you since it is extremely dark. 
  • Make through the narrow passageways and turn right from one of the drops in the cliff, and players can come across a massive hole in the ground
Hole In The Ground
Hole In The Ground (Image Credits Exputer)
  • Jump into the hole, and you are brought inside a building
  • Go down the hallways, and use the maintenance key (discussed later) to open the door by interacting with the door by holding E
  • Turn right from the dead body infront of you, and keep running down until you come across a locked yellow door
Locked Yellow Door
Locked Yellow Door (Image Credits Exputer)
  • Open it, let the cutscene play, and continue making your way through the corridor. 
Running Through The Corridor
Running Through The Corridor (Image Credits Exputer)

One thing that players need to keep in mind is that there is a hell of a lot of enemies that are ready to pounce at you. Therefore, players need to be on their guard at all times. 

Level 2 Door
Level 2 Door (Image Credits Exputer)
  • Keep heading through the corridor, then make your way towards the teal-illuminated hallways (which weirdly resemble backrooms) and locate a door that is present at level 2

Level 2 Door 

White Illuminated Walls
White Illuminated Walls (Image Credits Exputer)

Once you’ve arrived at the level 2 door, head inside, run past the dead body in the room and turn right from the second room which has a door leading further in. 

  • The hallway inside has white illuminated walls, and from here, you find yourself inside an apartment
Golden Armor On Couch
Golden Armor On Couch (Image Credits Exputer)
  • The apartment leads you into a living room, and right on the living room couch, the golden armor is located

Why Do You Need Golden Armor?

Lastly, let’s take a quick look at the uses of the golden armor

  • The golden armor itself is a progression item that players can get their hands on, and once they have it in their arsenal, they don’t need to worry about it being lost or getting broken. 
  • The main use of the golden armor is to grant the player a full HP bar essentially
  • It is mostly focused on battles where players use ranged attacks rather than melee-based attacks. 
  • The armor is also used in the form of a key to open the arm door. 

Maintenance Key Location In Sons Of The Forest

Last but not least, players need the maintenance key to open up the arm door, and the maintenance key is also needed to get the armor suit

Right End Of Island
Right End Of Island (Image Credits Exputer)
  • Players need to make their way down towards the bottom right area of the island, a bit to the eastern side of the snowy mountains, and players need to travel around the mountains and then make their way down. 
  • Players need to get their hands on a shovel for this process. 
  • Locate an area where there are yellow leaves on the ground, and the area seems suspiciously well-protected. 
Square Entrance
Square Entrance (Image Credits Exputer)

As soon as you start digging into the ground, a square entrance pops up, which leads deeper inside the ground. 

  • Interact with it by clicking or holding E, and as you head down the ladder, you are met with a mildly illuminated room. 
Going Through The Corridor
Going Through The Corridor (Image Credits Exputer)
  • Start making your way down the long corridor until you encounter a door on your right
Furnished Apartment
Furnished Apartment (Image Credits Exputer)
  • As you head inside the door, you are met with a perfectly furnished apartment and a table on the far end of the room with a 3D printer on it
Interacting With Key
Interacting With Key (Image Credits Exputer)
  • Towards the right side of the table, the maintenance key is located, and players can pick it up by interacting with it. You can also pick up an album cover which is present right next to the tv. 
Maintenance Key Obtained
Maintenance Key Obtained (Image Credits Exputer)

The maintenance key can be used to get your hands on the Katana as well. 


And there we have it! All that players need to know about the Sons Of The Forest Arm Door, and with that, we will wrap up our guide! While we’re here, why not read up on our Sons Of The Forest How To Make Rope guide which goes in detail about how you can make a rope! If you’ve wanted to know a solid source of water in the game, then our Sons Of The Forest Get Water Collector guide will tell you all there is to know!

Apart from this, you might also really like our Sons Of The Forest Quick Select guide since it goes in depth about the uses of the quick-select in-game. 

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Mina Anwar

Mina is a Senior Guides Writer and a fanatic who’s obsessed with playing games and writing about them. She’s invested more than 2,500 hours in games like Genshin Impact and Honkai Star Rail. With a Bachelor’s Degree in Journalism, she loves to write detailed guides for beginners and pros in the Gacha Games world. You can follow Mina's gaming activity on her Steam and PSN Profiles. Experience: 3+ Years || Education: Bachelor's in Journalism || Written 400+ Articles

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