We love a challenge. Like the challenge of figuring out which fire-stairs-looking door is the actual entrance to a cool underground bar, or how long we'll have to walk down this seemingly endless passageway before we can get a cocktail in our hands. Does this passageway even lead to a bar, or will we end up at a rubbish room staring at a confused line cook bringing out the bins?

Don't worry, we've done the underground bar exploration so you won't get lost. Here are five of our favourite underground bars in Sydney.

Soul Trap

5 underground bars to hide out in this weekend

If you've been to Pocket Bar, the eclectic, left-of-centre design of Soul Trap might feel vaguely familiar. Owner Christophe Lehoux was one of Pocket Group's founders, but he sold his share to open this Surry Hills underground bar that's one part moodily-lit, soul music hideaway, and one part milliner's workshop.

Although Christophe has been in Australia for many years, his French roots shine on Soul Trap's menu. Make sure to try one of the mistlles, a French spirit that's sweet and delicious like an aperitif wine. Small plates include tartines (think French bruschetta) and an incredible range of cheeses, charcuterie and pickled vegetables.

70-72 Campbell St Surry Hills

Bridge Bon Appétit

5 underground bars to hide out in this weekend

Bridge Bon Appétit is a lesson in clever use of space. It occupies a long wide bridge that reaches over Hubert's main dining room. There are just 45 seats, and the kitchen and bar are in a combined space, but that doesn't mean they can't churn out some seriously incredible food and drink.

Part of the Swillhouse family, Bridge Bon Appétit's drinks list is short and innovative. Try the Fumé, a drink that's made with triple smoked blueberry juice they make in house plus whisky, figs, caramel and lemon.

Basement, 15 Bligh St Sydney

The Doss House

5 underground bars to hide out in this weekend

Come to Doss House for the whisky, stay for the history lesson. Every of the four small rooms and two terraces that make up Doss House's small space are inspired by the many tenants that have occupied this sandstone building over the last 170 years. There's the Bootmaker's Workshop with its original fireplace, bookshelves and leather chesterfield and armchairs, or Ung Quoy's Den, named for a Chinese tenant who ran an opium den out of the space.

The drinks menu is heavy on whisky, but there are also amazing rum cocktails and, given the owners are Irish, Guinness on tap. 

77-79 George St The Rocks, Sydney

Door Knock

5 underground bars to hide out in this weekend

The key to Door Knock isn't a key at all, it's a yellow ceramic pineapple door knocker. Bang it three times and the door will open to a dimly lit, underground oasis with hanging plants, and plenty of comfortable, sheepskin rug-lined seating perfect for big groups of friends or a cosy date night.

Sit at the bar to watch the bartenders at work on Door Knock's unusual and delicious cocktails. The Caskhopper, a whisky, espresso and coconut milk drink is creamy and warming with a hint of chocolate mint. The Kiwi As is Door Knock's take on a spritz. It's made from vermouth, gin, lemon thyme and a dash of apple cider vinegar.

B2, 70 Pitt St Sydney

The Baxter Inn

5 underground bars to hide out in this weekend

Also part of the Swillhouse Group, the Baxter Inn is the older brother to Bridge Bon Appetit and Hubert. It's another whisky focused bar, but given the strength of the spirit, The Baxter's offering runs from approachable (for newbies) to those who appreciate a peaty, aged drink.

Complementing the 800-strong whisky list, the Baxter also does killer cocktails. Try a regular old negroni or their version of a whisky sour. There's no menu here, so if you're hungry, wander down the laneway to the Duke of Clarence pub for a fish finger sandwich and a glass of boozy punch.

Rear Basement 152-156 Clarence St Sydney 

5 underground bars to hide out in this weekend