The following are known Action Replay Codes for Sonic the Hedgehog 3 on SEGA Genesis / Mega Drive (Genesis).

The codes should work with the region specified but may work for other regions as well.

Device Compatibility: Action Replay

• Enable Stage Select 1
  FFFFD0:0100
• Enable Debug Mode
  FFFFFA:0100
• Enable Debug Mode (On An Actual System)
  00362A:0001
• Infinite Rings 2
  FFFE20:00C8
• Infinite Lives
  FFFE12:0009
• Only Need 1 Blue Sphere For Chaos Emerald
  FFE438:0001
• Only Need 1 Blue Sphere For Chaos Emerald (On An Actual System)
  FFE439:0001
• Stage/Act Modifier 3
  FFFE10:XXYY
• All Emeralds Collected
  FFFFB0:0007
• Stop Timer
  FFFE24:000F
• Ultimate Invincibility! 4
  FFB029:6600
• Ultimate Invincibility! (On An Actual System)
  FFB02B:0066
• Super Speed! [Sonic]
  FFF761:6419
• Super Speed! [Tails]
  FFFEC1:6419
• Flashing As If Super
  FFF65D:FF00
• Super Fast
  FFF760:1600
  FFF762:0046
• All Powerful! [Invincible, Aqua Breathe, Magnetism]
  FFB02A:006E
• Yellow & Flashes, As If Super Sonic
  FFF65E:04FF
• Switch F/X On For Levitate Jump For Sonic
  FFB01A:FE
• Switch F/X On For Levitate Jump For Tails
  FFB05A:FE
• Level Select Automatically Highlighted On Start Menu
  FFFF86:02
• Hyper Mode P1
  FFB024:00
• Hyper Mode P2
  FFB06E:00
• Special Ring Always Available
  FFFF95:00
• HUD Display Modifier 5
  FFF711:??
• Hacc’s Difficulty Mode 6
  FFF730:00
• Rings Multiplier 7
  FFF710:00

Footnotes

• At the title screen, hold the A button and push Start to enter the stage select menu.
• This code also allows you to pass the special stages with ease, and always get the Chaos Emerald at the end.
• Quantity Digits for “yy”(Stage):

  00 – Angel Island
  01 – Hydrocity
  02 – Marble Garden
  03 – Canival Night
  04 – Flying Battery (?)
  05 – Icecap
  06 – Launch Base
  07 – Mushroom Valley (?)
  08 – Sandopolis (?)
  0E – ???? (2p game?)
  0F – ???? (2p game?)
  10 – ???? (2p game?)
  11 – ???? (2p game?)
  12 – ???? (2p game?)
  13 – Bonus Stage (?)
  16 – ???? (!)
  17 – ???? (!)

  Quantity Digits for “yy”(Act):

  00 – Act 1
  01 – Act 2
  02 – Act 3

  Not all stages have acts 2 or 3.

• Invincible, bullet shield, underwater breathing, and magnetism.
• Also affects the rings. You can still collect them.

  00 – Off
  01 – On

• Hahaha! Try and beat the game now without using any codes.
• Cheesy, yet satisfying.