Borderlands 4 Co-Op & Multiplayer Guide 2026: Loot Scaling, Best Team Comps & Connection Fixes

We lost a Mayhem 10 raid boss kill because our fourth player disconnected at 10% health and the boss's HP didn't scale back down. Borderlands 4's co-op scaling is permanent once a player joins — if they leave, the difficulty stays locked until you restart. Here's everything the game doesn't tell you about playing with friends.

Co-op scaling: the real numbers

Enemy health per player: 1p = 100% base, 2p = 175%, 3p = 250%, 4p = 350%. Enemy damage: 1p = 100%, 2p = 115%, 3p = 130%, 4p = 150%. Enemy count also increases — more badasses and anointed spawn. A 4-player session has roughly 2.5x more enemies AND they have 3.5x health AND deal 1.5x damage.

Critical detail: scaling LOCKS when a player joins and does NOT scale back down. If two players leave a 4-player session, enemies stay at 4-player scaling. Restart the session to reset.

Loot drops per player: 1p = 100%, 2p = 140%, 3p = 180%, 4p = 220%. Over a 2-hour session, 4 players get roughly 40% more legendaries per player than solo.

Loot instancing: Cooperative vs Coopetition

Two modes at character creation: Cooperative (each player sees their own loot) and Coopetition (shared loot pool — everyone fights for drops). Pick Cooperative. Always. Legendary drops are instanced per player in Cooperative — four different legendaries can drop from one boss, each player gets their own.

Quest rewards are always instanced. Boss dedicated drops are instanced in both modes (each player gets their own roll). World drops from trash mobs are instanced in Cooperative, shared in Coopetition.

Best team compositions

2-player: Soldier + Gunner (turret aggros, Gunner deletes), Beastmaster + Siren (pet tanks, Siren flank — highest mobility), Soldier + Beastmaster (safest — two aggro sources).

3-player: Soldier + Gunner + Siren (turret tank, Gunner DPS, Siren flex).

4-player ideal: Soldier (turret + team shields) + Gunner (primary DPS) + Siren (elemental debuffs) + Beastmaster (pet off-tank + crit support).

Don't stack multiple Gunners or Sirens. Gunners compete for shared ammo drops. Siren elemental debuffs don't stack.

Level syncing

High-level joining low-level host: scaled DOWN to host level. Gear scales proportionally. All skill points kept — you'll be noticeably stronger than a natural player at that level. Low-level joining high-level host: scaled UP to host level minus 2. Gear does NOT scale up — drop them level-appropriate gear immediately.

Connection fixes

1. Both restart game (forces new SHiFT auth, fixes ~40% of issues). 2. Check NAT — both need Open or Moderate. Port forward TCP 7777, UDP 7777-7788, UDP 27015-27030. 3. Crossplay must be ON for ALL players even on same platform. 4. SHiFT outages happen roughly twice monthly on Tuesday mornings — no fix, just wait. 5. LAN bypasses SHiFT entirely for same-house play.

Mayhem syncing: All players must have unlocked the host's Mayhem level. Host sets modifiers. Coordinate rerolls before session.

Warning: Don't pick up modded weapons in public lobbies. They can corrupt your save file. I've lost a 120-hour character to a modded launcher that broke bank storage.