Ang mga side mission sa Borderlands 4 ay mahalaga para sa sinumang Vault Hunter na nagnanais maranasan ang buong kaguluhan ng Kairos. Sa kabuuang 93 side mission na nakakalat sa iba't ibang rehiyon, bawat quest ay nag-aalok ng natatanging mga gantimpala mula sa Vault Hunter Styles at mga weapon skin hanggang sa vehicle paint jobs at mga cosmetic na ulo.

The Fadefields

Coastal Bonescape

• Meat is Murder - Gantimpala: Tropic of Cairn (Vault Hunter Style)
• Abduction Injunction
• Hangover Helper - Gantimpala: Soused (Vault Hunter Style) x2

Hungering Plain

• No Place Like Home - Mga Gantimpala: Crimson Takeover (Vault Hunter Style), Crimson Takeover (ECHO-4 Paintjob)

The Low Leys

• Exit Through the Rift Shop - Gantimpala: Absolute Astra (Vault Hunter Style)

The Howl

• Ready to Blow - Mga Gantimpala: Taste Municipality (Vault Hunter Style, ECHO-4 Paintjob)
• Breeding Daisies - Gantimpala: It’s Threshy! (Vault Hunter Head)
• Whack-A-Thresher
• Carried Away
• Droning On
• Drone Ranger
• The Kairos Job - Gantimpala: Smiley (Weapon Skin)
• Scoundrel Roundup: Glitch
• Scoundrel Roundup: Kilo
• Free for the TASKing
• TASK and Ye Shall Receive
• TASK Master
• Working For Tips
• Null and Void - Gantimpala: Out of Bounds (Vault Hunter Style)
• All Charged Up - Gantimpala: Out of Bounds (ECHO-4 Paintjob)
• Bound for Launch
• PowerDrop
• Savage Salvage

Idolator’s Noose

• Sum of His Parts - Gantimpala: Bargain Hunter (ECHO-4 Paintjob)
• Electroshock Therapy
• Electroshock Therapy: The Second Session

Dissected Plateau

• Gone Are My Leggies - Gantimpala: Halt, Citizen (Vehicle Paint Job)
• To the Limb It
• To the Limb It: Redux
• To the Limb It: Couples Therapy
• Primordial Vault: Fadefields

Carcadia Burn

Lopside

• Potty Mouth - Gantimpala: ECHO-IVIV (ECHO-4 Frame)
• Imminent Jest

Grindstone of the Worthy

• The Power Ballad of Rodd Vomit - Gantimpala: Trendy Collection (Vault Hunter Head)
• Vicious News Cycle: Cannon Fodder
• Primordial Vault: Carcadia Burn

Ruined Sumplands

• Fault Hunting - Gantimpala: Eternal Defender (Weapon Skin)
• Vend of the Line
• Enter the Electi Part 1
• Enter the Electi Part 2
• The Council Divided - Gantimpala: Middle Name “Danger” (Vault Hunter Style)
• A Traitor Within — Gantimpala: Middle Name “Danger” (ECHO-4 Paintjob)
• The Mole’s Gambit - Gantimpala: Cursed to Live (Vault Hunter Head)
• PB&J
• Her Own Funeral
• Broken Ships
• Vicious News Cycle: Hot Tag
• Vicious News Cycle: Mine Time Live

Tonnage Peel

• And Welcome to the Jam
• Ripples and Rituals

Terminus Range

Hungering Plain

• Finway’s Cup

Cuspid Climb

• Flat Kairoser - Mga Gantimpala: Flat as a Fritter (Vault Hunter Style, ECHO-4 Paintjob)
• Peak Performance
• Wayward Gun - Mga Gantimpala: Loyal Customer (Vault Hunter Style, ECHO-4 Paintjob)
• Way Too Chill

Stoneblood Forest

• Father of the Glide
• Crack This Guy’s Back
• Sage Against the Machine
• The Next Quest Thing

The Low Leys

• Mob Mentality - Gantimpala: Claver (Vault Hunter Style)
• Mob Rules - Gantimpala: Claver (ECHO-4 Paintjob)
• Angry Mob - Gantimpala: More Human (Vault Hunter Head)
• Mob Justice - Gantimpala: Criminal Enterprise (Vault Hunter Head)
• Tandem Access Memory
• La-La-Last Call
• Ain’t No Sham in It
• Brew-ha-ha
• Never Meet Your Heroes
• The Importance of Being Furnished
• A Brother in Need
• It’s a Whole Phase Situation - Gantimpala: Earned Your Stripes (Vault Hunter Style)
• Returned to the Mountain
• A Call for Help
• Primordial Vault: Terminus Range

Dominion

Carcadia District

• Price of Freedom
• Price of Freedom Pt. 2
• Price of Freedom Pt. 3
• Joe & Sue
• The Black Market
• Overwriting a Wrong
• Bad Seed
• Bad Seed Pt. 2
• The Cat’s Pajamas

Terminus District

• AAA for Effort
• Below the Surface
• No-Escape Room - Gantimpala: Eternal Defender (Vehicle Paint Job)
• Love in the Time of Eridium Poisoning

Fades District

• Old Raymond
• Old Lads
• Old Tricks
• One Gassy Issue
• One Slimy Issue

Sa halos isang daang side mission na nakakalat sa Kairos, ang Borderlands 4 ay nag-aalok ng mas maraming iba't-ibang karanasan kaysa sa anumang entry sa serye hanggang ngayon. Kung ikaw ay naghahanap ng legendary loot, nakakatawang one-off questlines, o mga cosmetic na gantimpala, ang pagsasagawa ng mga side mission na ito ay magpapanatili sa iyo na abala kahit matapos na ang credits.