The following are known Game Genie Codes for Sonic the Hedgehog 3 on SEGA Genesis.

• You Do Not Lose Rings
  AWHA-CA92
• You Can Access the Sound Test Menu From Title Screen
  D3AT-AR2E
  Note: Press Up when you get the options and you can access the Sound Test. This code also enabled a Level Select option.
• Rings Worth 2
  SCGT-DJYL
• Rings Worth 3
  SCGT-DNYL
• Rings Worth 4
  SCGT-DTYL
• Rings Worth 5
  SCGT-DYYL
• Rings Worth 6
  SCGT-D2YL
• Rings Worth 7
  SCGT-D6YL
• Rings Worth 8
  SCGT-DAYL
• 75 Rings Needed For A Free Guy
  KRGT-CAE0
• 50 Rings Needed For A Free Guy
  GLGT-CAE0
• 30 Rings Needed For A Free Guy
  D4GT-CAE0
• 20 Rings Needed For A Free Guy
  CWGT-CAE0
• 10 Rings Needed For A Free Guy
  BLGT-CAE0
• Get 2 Free Guys For 100 Rings Instead Of 1
  HCGT-DJZY
• Get 3 Free Guys For 100 Rings
  HCGT-DNZY
• Get 4 Free Guys For 100 Rings
  HCGT-DTZY
• Get 5 Free Guys For 100 Rings
  HCGT-DYZY
• Get 6 Free Guys For 100 Rings
  HCGT-D2ZY
• Get 7 Free Guys For 100 Rings
  HCGT-D6ZY
• Get 8 Free Guys For 100 Rings
  HCGT-DAZY
• Super Ring Powerup Worth 0
  AC5A-CAHN
• Super Ring Powerup Worth 5 Instead Of 10
  A05A-CAHN
• Super Ring Powerup Worth 15
  B85A-CAHN
• Super Ring Powerup Worth 20
  CW5A-CAHN
• Super Ring Powerup Worth 25
  DG5A-CAHN
• Super Ring Powerup Worth 30
  D45A-CAHN
• Super Ring Powerup Worth 50
  GL5A-CAHN
• Super Ring Powerup Worth 100 (1-Up Every Time)
  NW5A-CAHN
• Super Sonic Doesn’t Lose Rings
  AJZA-CA8N
• Infinite Lives
  AJ3A-CA7A
• Start With 1 Life
  AG4T-AAH4
• Start With 2 Lives
  AL4T-AAH4
• Start With 5 Lives
  A04T-AAH4
• Start With 10 Lives
  BL4T-AAH4
• Start With 25 Lives
  DG4T-AAH4
• Start With 50 Lives
  GL4T-AAH4
• Start With 99 Lives
  NR4T-AAH4
• Shield Can Be Activated Multiple Times
  ACAT-CAB6
• Invincibility Power-Ups Last Forever
  AJRT-CA8R
• Invincibility Lasts Almost Twice As Long
  986A-CAB6
• Invincibility Lasts Half As Long
  KR6A-CAB6
• Invincibility Lasts 1/4 As Long
  E06A-CAB6
• Only Need 6 Chaos Emeralds
  SCFT-BJT4
• Only Need 4 Chaos Emeralds
  SCFT-BNT4
• Only Need 3 Chaos Emeralds
  SCFT-BTT4
• Only Need 2 Chaos Emeralds
  SCFT-B2T4
• Blue Spheres Worth 2
  SCGA-BL0N
  A4GA-A28T
• Blue Spheres Worth 3
  SCGA-BR0N
  A4GA-A28T
• Blue Spheres Worth 4
  SCGA-BW0N
  A4GA-A28T
• Blue Spheres Worth 5
  SCGA-B00N
  A4GA-A28T
• Blue Spheres Worth 6
  SCGA-B40N
  A4GA-A28T
• Blue Spheres Worth 7
  SCGA-B80N
  A4GA-A28T
• Blue Spheres Worth 8
  SCGA-BC0N
  A4GA-A28T
• 1 Blue Sphere Needed For Chaos Emerald
  ACGA-AA8T
• Bonus Jump
  TAYA-CRB6
• Super Jump
  AAYA-CWB6
• Mega-Jump
  AAYA-C0B6
• Never Drown (Must Switch Off For Some Spring-Pad Jumps)
  ATST-CA38
• Super Fast
  AD59-9NDA
  J559-8ADC
• All Powerful! [Invincible, Aqua Breathe, Magnetism]
  P42S-8ABL
• Yellow & Flashes, As If Super Sonic
  995S-8JC8
• Enable Debugger
  AE5A-AABL
  Note: When playing on an emulator and using this code you may need to reset the game after enabling the code.
• Trick The Game Into Thinking You Are Playing As Knuckles
  ASCA-AAHC
  ASCA-BA9Y
• Tails Runs Differently #1
  GVWA-CA42
• Tails Runs Differently #2
  GVWA-CA4E
• Tails Runs Differently #3
  GVWA-CA40
• Tails Runs Differently #4
  GVWA-CA44
• Tails Never Get Tired of Flying
  VPLA-CACG
• Tails Always Swims
  AFLA-CARE
• Sonic Can Now Use Electric Jump
  AAYT-CAY4
• Sonic’s Flash Attack, Fireball, Bubble Bounce Are Disabled
  AAYT-CAA8
• Sonic Can Now Use Fireball
  AAYT-CAWT
• Sonic Can Now Use Bubble Bounce
  AAYT-CAGC
• Become Super Sonic With 0 Rings
  AAYT-CAH0
• Don’t Use Up Rings To Maintain The Transformation of Super Sonic
  AAZA-CAEY
• Become Super Sonic With 0 Emeralds
  AAYT-CAHR
• Tails Fast Run
  ABLT-CA9Y
• Sonic Pick Up Speed
  AJOT-CAGT
• Tails Can’t Spin Dash
  ABRT-CATN
• Tails Is Very Light
  ABLT-CAR2
• Invincibility
  ATLA-CARA
• Tails Always Swims
  AFLA-CARE