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.
The following missions represent plot progression. Typically they have no time limit, and you can pursue side quests while they are available. Exceptions will be noted.
- 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.
- 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.
- 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.
- 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.
These missions are issued or can be found as the game progresses. They are sorted according to the Priority mission after which they become available. Character names in parentheses have a possibility of making an appearance in the mission, provided they're alive.
Priority: The Citadel
- N7: Cerberus Lab
- Shrike Abyssal: Prothean Obelisk
- Priority: Eden Prime (Requires the DLC pack From Ashes.)
- Kite's Nest: Pillars of Strength
- Citadel: Hanar Diplomat (Kasumi Goto)
- Benning: Evidence
- Citadel: Improved Power Grid
- Apien Crest: Banner of the First Regiment
- Aria: Blood Pack
- Aria: Blue Suns
- Aria: Eclipse
- Citadel: Alien Medi-Gel Formula
- Citadel: Biotic Amp Interfaces
- Ismar Frontier: Prototype Components
- Citadel: Barla Von
- Citadel: Heating Unit Stabilizers
- Grissom Academy: Emergency Evacuation (Jack) (Note: This mission is timed and will be marked as failed if not completed within three missions after becoming available.)
- Irune: Book of Plenix
- N7: Cerberus Attack
- Citadel: GX12 Thermal Pipe
- Tuchanka: Turian Platoon (Unlocks Priority: Tuchanka.)
- Attican Traverse: Krogan Team (Grunt) (Unlocks Priority: Tuchanka.)
Priority: The Citadel II
- Arrae: Ex-Cerberus Scientists (Jacob Taylor)
- Kallini: Ardat-Yakshi Monastery (Samara)
- Athena Nebula: Hesperia-Period Statue
- Citadel: Batarian Codes
- Citadel: Cerberus Ciphers
- Citadel: Cerberus Turian Poison
- Citadel: Kakliosaur Fossil
- Citadel: Medical Supplies
- Citadel: Reaper Code Fragments
- Citadel: Target Jamming Technology
- Citadel: Volus Ambassador (Zaeed Massani)
- Citadel: Cerberus Retribution
- Citadel: Chemical Treatment
- Citadel: Inspirational Stories
- Citadel: Medi-Gel Sabotage
- Citadel: Wounded Batarian
- Dekuuna: Code of the Ancients
- Hades Nexus: Obelisk of Karza
- Hades Nexus: Prothean Sphere
- Nimbus Cluster: Library of Asha
- Silean Nebula: Rings of Alune
- Valhallan Threshold: Prothean Data Drives
Priority: Geth Dreadnought
- Rannoch: Admiral Koris (Note: This mission will not be available after completing Priority: Rannoch)
- Rannoch: Geth Fighter Squadrons (Note: This mission will not be available after completing Priority: Rannoch)
- N7: Fuel Reactors
|Mass Effect 3 Guides|
|Completion||Walkthrough • Morality • Search and Rescue • Equipment and Items|
|Classes||Adept • Engineer • Infiltrator • Sentinel • Soldier • Vanguard|
|Other||Squad Members • PC Tweaks • Interrupts • Merchants • The One and Only|