After the Emerald Grove stops being the party’s favorite roadside attraction and the Goblin Camp is either charmed, flattened, or thoroughly confused, Baldur’s Gate 3 tosses out one of those classic fantasy road trips: keep things sunny up top, or descend into a glowing hole full of mushrooms and regret. The Mountain Pass and the Underdark both promise a route toward Act 2, but they are not even close to being the same vibe. One is a brisk walk with a side of githyanki drama. The other is a sprawling underground soap opera with anvils, mind-controlled gnomes, and a forge that slaps.
The Mountain Pass: Lae’zel’s Big Field Trip
For anyone who has ever wanted to speedrun their way into Act 2 while picking up a legendary mace and hearing Lae’zel complain about local architecture, the Mountain Pass is the ticket. This overland route sits east of the Goblin Camp and winds through hills that are, frankly, way less likely to dissolve someone’s boots than the Underdark. It is the “quick and easy” option, relatively speaking.
The number one reason to take the Mountain Pass is simple: it is basically Lae’zel’s personal story arc disguised as a geography lesson. She has been yapping about a githyanki crèche since the nautiloid crashed, and lo and behold, that crèche is parked right along the Mountain Pass. Any player who wants to keep their favorite angry alien happy should definitely take this route. Just know that solving the mind flayer parasite problem is not as easy as the brochure suggests.
Loot goblins also have a reason to grin. The abandoned Rosymorn Monastery is full of puzzles, holy vibes, and the Blood of Lathander, a legendary weapon that can turn undead encounters into a hilarious light show. The weapon even comes with Sunbeam, which is just a polite way of saying “delete that vampire.”
For players who want minimal fuss, the Mountain Pass is a no-brainer. It is shorter, less crowded, and offers fewer opportunities to accidentally start a war with a talking mushroom.
The Underdark: Fungus, Forges, and Feral Gnomes
Then there is the Underdark, which is less of a path and more of an entire underground DLC that Larian forgot to label as optional. It can be reached through the Defiled Temple, several other hidey-holes, or by simply falling into the wrong hole and hoping for the best. It is bigger, stranger, and packed with enough content to make a completionist’s eyes water.
The Underdark does not revolve around one companion the way the Mountain Pass revolves around Lae’zel. Instead, it offers a buffet of narrative chaos. There is a Myconid colony full of fungal friends who need help with a squabble, and a place called Grymforge that is currently being run by the Absolute’s least cheerful employees. Grymforge houses the Adamantine Forge, where the party can craft some of the best early-game weapons and armor, provided they first survive a boss that hits like a freight train with self-esteem issues.
There are also deep gnomes to rescue. Barcus Wroot fans, take note: skipping the Underdark means skipping a big chunk of his story. Nobody wants to be the player who left Barcus hanging. That is how guilt is made.
For players who enjoy poking around every corner, the Underdark also delivers a defense-laden Arcane Tower and more environmental storytelling than a nature documentary. It is a bigger time sink, but the rewards are worth the heartburn.
You Can Do Both, and the Order Is Not That Deep
Here is the good news: taking one route does not lock the other one away forever. Baldur’s Gate 3 is generous enough to let the party double back before the real point of no return. Act 2 has a cutoff, but it is not hiding right at the door, so there is room to mop up missed content.
Still, the smarter play for most campaigns is to hit the Underdark first. It is the bigger, meatier area, and reaching Act 2 from the Underdark feels like a natural progression. After that, the party can swing back through the Mountain Pass, grab the Blood of Lathander, and make Lae’zel slightly less grumpy. Going the other way works too, especially if the party is underleveled and not ready for the Underdark’s nonsense, but returning to the Underdark after Act 2 can feel like wandering back into a basement after the party has already moved upstairs.
For players who absolutely refuse to do both, the Underdark is the better choice. Skipping it means losing more gameplay, more loot, and more Barcus-related emotional damage. The Mountain Pass is lovely, but it is ultimately a side quest compared to the Underdark’s main-course energy.
| Route | Best for | Watch out for |
|---|---|---|
| Mountain Pass | Lae’zel fans, loot lovers, speedrunners | Githyanki attitude, puzzle-related headaches |
| Underdark | Completionists, forge enjoyers, Barcus protectors | Mushroom politics, angry duergar, gravity |
The Verdict: Go Underground, Then Apologize to Lae’zel Later
A savvy adventurer in 2026 knows that Baldur’s Gate 3 rewards curiosity. The Underdark offers more bang for the buck, more weirdos to befriend or betray, and better gear for the road ahead. The Mountain Pass is a delightful detour, but it is not the main event. Do both if possible, but if the party must choose, send them into the dark. The fish people down there have opinions, and honestly, they are kind of fun.