Quick Links
If you think the first act of Baldur's Gate 3 is only about the island you have crashed onto, you are dead wrong. There is an entire world lying beneath this island with much more dangerous enemies and a brutal environment.
The Underdark is a massive world on its own to explore, but firstly you need to learn how to get there. Thankfully, there are multiple ways to head into the Underdark, and this guide will go over all of them, from the easiest routes to the hardest ones.
Updated by Mehrdad Khayyat on August 7, 2023: We updated the way you need to solve the Stone-Disk puzzle inside the Goblin Camp.
Route 1: Blighted Village
This is indeed the easiest way to get to the Underdark, but only if you have spells like "Feather Fall" that could prevent or reduce fall damage. As the title implies, you need to head inside Blighted Village. This village is located on the western side of the Roadside Cliffs or Silvanus' Grove fast travel stations. So, you simply need to head west from any of these checkpoints until you reach a stone bridge.
As soon as you pass over the bridge, you will find yourself at the entry gate of Blighted Village. Keep in mind that this village is attacked by Goblins and upon your entrance, you will be interrupted by a Goblin. You can either fight with him or convince him through your Persuasion, Intimidation, or Deception skills.
Moving a few steps forward to the middle of the village will reveal the fast travel station of Blighted Village, in front of which there is a well. If you interact with the well, you will have the option to jump inside it.
Once you are inside, continue the way forward. While you can sneak around the spiders and other enemies in the first room, this could be quite time-consuming and difficult. This is why we suggest you accept the first fight against the enemies. There are three Spiders and two smaller enemies in this location. Once you deal with them, follow the path shown in the images above, and as soon as you reach that ledge passage with unique white lighting above it, switch to Stealth mode.
If you move forward here, you will have to fight with a giant spider, which is quite difficult to beat. Since your goal is to reach the Underdark, it's best to avoid the fight if possible. Now, jump down from the ledge. You are strongly suggested to ungroup your characters from here.
While you are still in Stealth mode, guide your character to follow the path drawn in the images above. There are two spiders here that you need to avoid getting in their sight. Once you are standing next to the deep well, cast the Feather Fall spell and jump inside the well. A cinematic video will play right after, and you will find your character in the Underdark. Do the same for other characters as well.
It doesn't matter if other characters don't have the same spell. They will die as soon as they land in the Underdark, but your alive character can revive them all.
Route 2: Zhentarim Hideout
Before we get into full details, keep in mind that this route requires lockpicking. So, make sure you have a bunch of lockpicks before starting the journey. If you haven't found the Zhentarim Hideout yet, it is located north of Blighted Village.
As soon as you exit Blighted Village from the northern gate, take the route to the northwest and pass over the broken bridge. Then, take the northwest route again until you reach a new village bounded by flame. Go inside the village, and then you will find a passage on your left, but the ground is on fire. Jump over the fire and follow the route to the west until you see a dead Ox on the ground. On the northern side of the Ox, there is a shabby door blocked by a few boxes. Destroy boxes and enter that room.
You will be now interrupted by an NPC. Kill him, and then look for a hatch inside the room that leads you to the Zhentarim Hideout. Once you are in, move ahead until you find a Wardrobe in a corner. Interact with it to find a hidden path. This will lead you to the depth of the hideout.
Move toward the iron gate, and then you will be interrupted by the gang's leader. You don't need to fight with her. So, just try to use your talkative skills to make your way inside. If you succeed, the iron gate will open up. Now, you need to search the entire hideout to find a wolf named "Istor." This wolf is standing in front of a rocky corner, but that rocky corner is indeed an illusionary wall. Shadowheart is the best character to successfully spot that illusion, which is why we suggest you lead your team with her at this part.
Once you've spotted the illusionary wall, it will glow, which means you can pass through it, but DO NOT do it. If you go through the wall in front of the wolf's eye, the entire camp will attack you. Instead, you need to ungroup all your characters, switch them into Stealth mode, and move them inside the hidden room one by one without the wolf noticing.
Inside this hidden room, there is an Elevator Winch. In order to make it work, you need to lockpick it. If you succeed, you can get on the elevator on the edge and head down to the Underdark.
Route 3: Goblin Camp
If you have already rescued Halsin from the Goblin Camp, or at least know where the Goblin Camp is, there is little to do this time. In case you don't know, the Goblin Camp is located on the west side of the Blighted Village. You pass over a wooden bridge, face a Goblin Outpost that you can either challenge in combat or sneak around, and finally make your way inside the Goblin camp through a broken stone bridge.
Once you are inside, head forward to the door behind the giant goblin. There will be another door ahead, but if you want to get through it, you need to convince the Goblin guard that you mean no harm. It can be done easily using your Illithid power or other deceiving skills.
As soon as you get inside the main hall with a big statue in the middle, turn left and go upstairs. You need to open the second door from the left. Once you are inside the room, open the Ornate Door in front of you. This will lead you inside a prison area with a giant Goblin guarding it.
You need to sneak around the Goblin and head to the open corridor. Ungroup all your characters, switch to Stealth mode, and navigate them one by one to the safe spot. At the end of this corridor, there is an entrance to another room marked by a guardian statue. Inside this room, there is a stone-disk puzzle that you need to solve to open the door on the other end of the room.
Stone-Disk Puzzle Solution
You need to order the disks similar to the images above. Four full moons on the top disk, four dark moons on the bottom disk, and two other full moons on the outer sides of each middle disk. If you do it correctly, the door will open up, and the ladder beyond that door will take you to the Underdark.
Route 4: Sunlit Wetlands
If you have happened to explore the southern parts of the island, then you may have found an old woman talking to two young men about a girl called Mayrine. While this is a quest of its own, the final route to the Underdark is tied to this quest to a certain degree.
We have to spoil this quest a little bit in order to explain the route to the Underdark. So, take this as a serious spoiler alert if you don't want this side story to be ruined for you.
If you follow the old woman to the south, you will reach a new area called Sunlit Wetlands. This is a beautiful but swampy location that does look suspicious. On the west side of this area, there is a house that belongs to the old woman, where you can also find Mayrine. If you insist on getting Mayrine out of that place, the old woman will turn hostile, but she will take Mayrine to a location behind the home's fireplace.
Before this happens, however, you will need to deal with the old woman's guards that will surround the house. If you survive, get inside the fireplace and go downstairs. You will meet the old woman once more inside this mysterious cave. She will disappear again, leaving you with a mysterious door that won't open until you find its trick.
How To Open The Mysterious Door
The door is similar to a large tree foot with the face of a creature carved on it. Talk to the door, and when your conversation is over, look at its right, where you can find four wooden Whispering Masks on a table. Each of your characters should pick up one mask, but DO NOT put them on for now.
Create a manual save, ungroup all your characters, and move three of them next to the stairs where you entered the cave from. Lead the remaining character to stand in front of the wooden door. Now, equip the mask, and you will be able to actually pass through the door.
Once you are on the other side, take off the mask as soon as possible.
This entire process of putting on and off the mask should be completed in around 5 seconds. If it takes longer than that, your character will be controlled by the magic of the old woman, and they will become hostile against other characters. This situation can only be resolved by killing the hostile character, which is not good at all. In order to avoid this, we suggested earlier moving other characters out of the masked character's sight.
Now bring back the other characters to the door one by one and repeat the same process for them. In order to be able to put off the mask quickly, do not close the inventory tab after wearing it.
Now, you may actually think what would happen if all characters wear the masks simultaneously and move through the door. Well, that is simply not possible as the masks will kill all your characters at the same time.
Navigating To The Waterfall
Once all your characters are on the other side of the door, you will spot more masked characters in here, but they will all be hostile to you. Sneaking past these NPCs is possible, but you can easily kill them all if you have a full squad at Level 4 or above. Your destination, however, is beyond a waterfall on the right side of the room, which is guarded by a masked NPC. You will need to use the Jump command to get to the other side of this waterfall.
As soon as all your characters are beyond the waterfall, there is a little path to reach the Underdark. Once you are on the other side, look to your right, and you will spot another of those wooden mysterious doors with a ledge in front of it. You need to jump onto that ledge and repeat the same mask-on/mask-off technique to go through it. Once you are on the other side of the door, you will spot a green magical plate. If you interact with the magic, you will be teleported to the Underdark.