At the versus screen, Player 1 enters the first 3 digits and Player 2 enters the last 3 digits. For the first digit, press Low Punch to cycle (0-9) then any other button to lock it in. For the second digit, use Block to cycle then lock. For the third digit, use Low Kick to cycle then lock. Codes only work in two-player matches.
| Effect | Player 1 | Player 2 | Notes |
|---|---|---|---|
| Gameplay | |||
| Player 1 Quarter Power | 7-0-7 | 0-0-0 | — |
| Player 2 Quarter Power | 0-0-0 | 7-0-7 | — |
| Player 1 Half Power | 0-3-3 | 0-0-0 | — |
| Player 2 Half Power | 0-0-0 | 0-3-3 | — |
| No Throwing | 1-0-0 | 1-0-1 | — |
| No Blocking | 0-2-0 | 0-2-0 | — |
| Silent Kombat | 3-0-0 | 3-0-0 | — |
| No Power Bars | 9-8-7 | 1-2-3 | — |
| Sans Power | 0-4-4 | 4-4-0 | — |
| Fast Uppercut Recovery | 6-8-8 | 4-2-2 | — |
| Psycho Kombat | 9-8-5 | 1-2-5 | — |
| Unlimited Run | 4-6-6 | 4-6-6 | — |
| Randper Kombat | 4-4-4 | 4-4-4 | — |
| Randper Kombat | 4-6-0 | 4-6-0 | — |
| Dark Kombat | 6-8-8 | 4-2-2 | — |
| Explosive Kombat | 2-2-7 | 2-2-7 | Only works in 2 vs 2 kombat |
| Explosive Kombat and Throwing Disabled | 0-2-2 | 2-2-0 | Only works in 2 vs 2 kombat |
| Arenas | |||
| Bell Tower | 0-9-1 | 1-9-0 | — |
| Jade's Desert | 3-3-0 | 0-3-3 | — |
| The Cave | 0-0-4 | 7-0-0 | — |
| The Balcony | 8-8-0 | 2-2-0 | — |
| The Temple | 6-0-0 | 0-4-0 | — |
| Waterfront | 0-0-2 | 0-0-3 | — |
| Rooftop | 3-4-3 | 3-4-3 | — |
| Scislac Busorez | 9-3-3 | 9-3-3 | — |
| Scorpion's Lair | 6-6-6 | 4-4-4 | — |
| Soul Chamber | 1-2-3 | 9-0-1 | — |
| The Bridge | 0-7-7 | 0-2-2 | — |
| The Graveyard | 6-6-6 | 3-3-3 | — |
| The Pit III | 8-2-0 | 0-2-8 | — |
| The Street | 0-7-9 | 0-3-5 | — |
| The Subway | 8-8-0 | 0-8-8 | — |
| Messages | |||
| Throwing Encouraged | 0-1-0 | 0-1-0 | — |
| Rain Can Be Found in the Graveyard | 7-1-1 | 3-1-3 | — |
| Whatcha Gun Do? | 0-0-4 | 4-0-0 | — |
| Hold Flippers During Casino Run | 9-8-7 | 6-6-6 | — |
| There Is No Knowledge That Is Not Power | 1-2-3 | 9-2-6 | — |
| Don't Jump at Me | 4-4-8 | 8-4-4 | — |
| Revision | 9-9-9 | 9-9-9 | — |
| Skunky !! | 1-2-2 | 2-2-1 | — |
| See the Mortal Kombat Live Tour !! | 5-5-0 | 5-5-0 | — |
| Hidden Fights | |||
| Winner Fights Smoke | 2-0-5 | 2-0-5 | — |
| Winner Fights Noob Saibot | 7-6-9 | 3-4-2 | — |
| Winner Fights Motaro | 9-6-9 | 1-4-1 | — |
| Winner Fights Shao Kahn | 0-3-3 | 5-6-4 | — |
In the Arcade version of UMK3, right after you lose a single-player game, the Ultimate Kombat Kode screen will appear. Input these commands to unlock a character:
| Character | Code |
|---|---|
| Ermac | 12344-44321 |
| Classic Sub-Zero | 81835-81835 |
| Mileena | 22264-22264 |
Each button changes a specific slot by cycling through symbols (0 to 9). Pressing a button increases that slot's number by 1.
| Player | Slot | Button |
|---|---|---|
| Player 1 | Slot 1 | Low Punch (LP) |
| Player 1 | Slot 2 | Low Kick (LK) |
| Player 1 | Slot 3 | Block (BL) |
| Player 1 | Slot 4 | High Kick (HK) |
| Player 1 | Slot 5 | High Punch (HP) |
| Player 2 | Slot 6 | Low Punch (LP) |
| Player 2 | Slot 7 | Low Kick (LK) |
| Player 2 | Slot 8 | Block (BL) |
| Player 2 | Slot 9 | High Kick (HK) |
| Player 2 | Slot 10 | High Punch (HP) |
