This page contains a walkthrough for the main missions of Mass Effect 3. Major changes in the gameplay from Mass Effect are listed in the main Mass Effect 3 page, while the effects of importing a saved game from Mass Effect 2 are listed in the Save File Transfer page.

Main Plot Edit

The following missions represent plot progression. They have no time limit, but each mission must be completed before the next becomes available.

Prologue Edit

• Prologue: Earth - Get to the Normandy SR-2 to escape Earth as the Reapers invade.
• Priority: Mars - Save Liara T'Soni from Cerberus and retrieve her data on the Crucible, a weapon capable of stopping the Reapers.
• Priority: The Citadel I - Begin rallying the other sentient races of the galaxy to the cause.

Act I Edit

• Priority: Palaven - Rescue a turian primarch with the help of Garrus Vakarian.
• Priority: Sur'Kesh - Hold a war summit with the turian, salarian, and krogan leaders, then protect a krogan female from a Cerberus attack.
• Priority: Tuchanka - Escort the krogan female and a salarian scientist to the Shroud to disperse a cure for the genophage.

Act II Edit

• Priority: The Citadel II - Save the Citadel Council from a Cerberus coup attempt.
• Priority: Perseus Veil - Meet with quarian representatives who wish to assist with the Crucible project.
• Priority: Geth Dreadnought - Help Tali'Zorah vas Normandy infiltrate and destroy a geth dreadnought before the Migrant Fleet is wiped out.
• Priority: Rannoch - Infiltrate a Reaper base on the surface of Rannoch to deactivate the signal upgrading the geth.
• Priority: The Citadel III - Meet with the asari Councilor to receive the location of a clue regarding the whereabouts of the Catalyst.
• Priority: Thessia - Reach an asari temple on Thessia to retrieve vital information as the Reapers devastate the planet.
• Priority: Horizon - Investigate Cerberus's connection to a refugee center on Horizon.

Act III Edit

Note: No side missions can be completed once you begin Act III, so finish up anything else you want to finish before heading to Cerberus Headquarters.

• Priority: Cerberus Headquarters - Assault Cerberus's headquarters to recapture a Prothean VI that can identify the Catalyst.
• Priority: Earth - Gather the galaxy's forces and launch the final battle to retake Earth from the Reapers and deploy the Crucible.

Side Missions Edit

These missions are issued or can be acquired as the game progresses. They are sorted according to the Priority mission after which they become available. The opportunity to complete certain side missions expires once specific main plot missions are completed. Others are marked as failed if not completed before a number of other missions are completed. These missions are noted below as "progress-sensitive missions" and "timed missions" respectively. Be aware that any side missions not completed before the main plot mission Priority: Cerberus Headquarters will no longer be accessible for the remainder of the game.

Note: Italicized mission names denote minor missions which can be completed merely through planet scanning, conversations, or finding an item during another mission.

Priority: The Citadel Edit

• N7: Cerberus Lab
• Priority: Eden Prime
  • DLC Mission: Requires the DLC pack From Ashes.
• Shrike Abyssal: Prothean Obelisk

Priority: Palaven Edit

• Apien Crest: Banner of the First Regiment
• Aria: Blood Pack
• Aria: Blue Suns
• Aria: Eclipse
• Citadel: Alien Medi-Gel Formula
  • Progress-Sensitive Mission: This mission expires if not completed before Priority: Tuchanka.
• Citadel: Aria T'Loak
  • DLC Mission: Requires the DLC pack Mass Effect 3: Omega.
• Citadel: Barla Von
  • Progress-Sensitive Mission: This mission expires if not completed before Priority: Tuchanka.
• Citadel: Biotic Amp Interfaces
• Citadel: Dr. Bryson
  • DLC Mission: Requires the DLC pack Mass Effect 3: Leviathan.
• Benning: Evidence
  • Progress-Sensitive Mission: This mission expires if not completed before Priority: Tuchanka.
• Citadel: Hanar Diplomat
  • Mass Effect 2 Squadmate Cameo: If recruited and alive, Kasumi Goto will appear in this mission.
• Citadel: Heating Unit Stabilizers
  • This mission cannot be completed before Priority: Tuchanka.
• Citadel: Improved Power Grid
  • Progress-Sensitive Mission: This mission expires if not completed before Priority: Tuchanka.
• Grissom Academy: Emergency Evacuation
  • Timed Mission: This mission expires if not completed before Priority: The Citadel II.
  • Mass Effect 2 Squadmate Cameo: If recruited and alive, Jack will appear in this mission.
• Irune: Book of Plenix
  • This mission cannot be completed before Priority: Tuchanka.
• Ismar Frontier: Prototype Components
• Kite's Nest: Pillars of Strength

Priority: Sur'Kesh Edit

• Attican Traverse: Krogan Team
  • Main Plot Progression: Unlocks the main plot mission Priority: Tuchanka.
  • Mass Effect 2 Squadmate Cameo: If recruited and alive, Grunt will appear in this mission.
  • Citadel: Krogan Dying Message
  • N7: Cerberus Abductions
• Citadel: GX12 Thermal Pipe
• N7: Cerberus Attack
• Tuchanka: Turian Platoon
  • Main Plot Progression: Unlocks the main plot mission Priority: Tuchanka.
  • Citadel: Cerberus Automated Turret Schematics
  • N7: Cerberus Abductions
  • Tuchanka: Bomb
    • Timed Mission: This mission will be marked as failed if not completed within three missions after acquisition.

Priority: Tuchanka Edit

• N7: Cerberus Fighter Base

Priority: The Citadel II Edit

• Arrae: Ex-Cerberus Scientists
  • Mass Effect 2 Squadmate Cameo: If alive, Jacob Taylor will appear in this mission.
• Athena Nebula: Hesperia-Period Statue
• Citadel: Batarian Codes
• Citadel: Cerberus Ciphers
  • This mission cannot be completed before Priority: Thessia.
• Citadel: Cerberus Retribution
• Citadel: Cerberus Turian Poison
• Citadel: Chemical Treatment
  • This mission cannot be completed before Priority: Geth Dreadnought.
• Citadel: Inspirational Stories
• Citadel: Kakliosaur Fossil
  • This mission cannot be completed before Priority: Geth Dreadnought.
• Citadel: Medical Supplies
• Citadel: Medi-Gel Sabotage
• Citadel: Reaper Code Fragments
• Citadel: Shore Leave
  • DLC Mission: Requires the DLC pack Mass Effect 3: Citadel.
• Citadel: Target Jamming Technology
• Citadel: Volus Ambassador
  • Mass Effect 2 Squadmate Cameo: If recruited and alive, Zaeed Massani will appear in this mission.
• Citadel: Wounded Batarian
• Dekuuna: Code of the Ancients
  • This mission cannot be completed before Priority: Rannoch.
• Hades Nexus: Obelisk of Karza
  • This mission cannot be completed before Priority: Rannoch.
• Hades Nexus: Prothean Sphere
  • This mission cannot be completed before Priority: Rannoch.
• Kallini: Ardat-Yakshi Monastery
  • Mass Effect 2 Squadmate Cameo: If recruited and alive, Samara will appear in this mission.
  • Citadel: Asari Widow
• Nimbus Cluster: Library of Asha
• Silean Nebula: Rings of Alune
  • This mission cannot be completed before Priority: Rannoch.
• Valhallan Threshold: Prothean Data Drives

Priority: Geth Dreadnought Edit

• N7: Fuel Reactors
• Rannoch: Admiral Koris
  • Main Plot Progression: Unlocks the main plot mission Priority: Rannoch.
  • Progress-Sensitive Mission: This mission expires if not completed before Priority: Rannoch.
• Rannoch: Geth Fighter Squadrons
  • Main Plot Progression: Unlocks the main plot mission Priority: Rannoch.
  • Progress-Sensitive Mission: This mission expires if not completed before Priority: Rannoch.

Priority: Rannoch Edit

• Dekuuna: Elcor Extraction

Priority: Thessia Edit

• N7: Communication Hub

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