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Despite not being as open as its predecessor, Mass Effect 3 gives you plenty of freedom regarding mission order. You need to do nearly all of the Priority quests in a set sequence, but you have more control over when you play each secondary operation. However, there are some risks to embarking on some adventures at the wrong time. After all, several missions are time or progression-sensitive, so those are easy to fail if you're not careful.

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Mass Effect 3 is a story-heavy game, and the order you do missions can positively or negatively impact the flow of the narrative. For instance, if you've just heard about a colony under attack, then it doesn't make sense for Shepard to spend the next few hours roaming around the Citadel. Therefore, if you want a playthrough that makes narrative sense and stops you from missing out on quests, then here's a guide.

Updated on February 11, 2023, by Gabrielle Huston: There's no worse feeling in the world than missing out on something just because you altered the order of a few missions! The ripple effect means that it can have lasting consequences. We've updated this guide to make sure you know everything you need to know in order to get the results you're looking for, including recommended companions, timed quests, and DLC content.

Prologue: Getting Back In Action

Mass Effect 3 Reaper Towering above city as ship flies past

The first few missions of Mass Effect 3 are all about the Reaper invasion and the galaxy's response to it. You are forced to play them in the order the game dictate

Mission Order:

Order

Mission

Notes

Recommended Companions

DLC

1

Prologue: Earth

2

Priority: Mars

3

Priority: The Citadel I

ACT 1: The Genophage

Mass Effect 3 Mordin close up with fire in the background

After visiting the Citadel for the first time, the game begins to open up. You have control of the Normandy and can go anywhere that's available. This section of the story focuses on Shepard trying to acquire the help of the Turians, Salarians, and Krogan.

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Optimal Mission Order:

Order

Mission

Notes

Recommended Companions

DLC

1

Priority: Eden Prime

You can do this operation at any time. In fact, it is DLC in the original version of the game, but you still probably want to complete it early as it gives you a new squadmate.

From Ashes

2

N7: Cerberus Lab

A small mission to give you more experience with the game's combat system.

3

Priority: Palaven

No reason to avoid this one, as unlike several Priority quests, starting it doesn't instantly fail others. Plus, it makes sense that Shepard would want to go there to gain Turian support straight away.

  • James
  • Garrus
  • Liara

4

Grissom Academy: Emergency Evacuation (aka Grissom Academy: Investigation)

You must do this one within three missions of Traynor telling you about it. The Specialist should give you the intel after the Palaven quest and the scene where EDI acquires her new body. It must be completed before Priority: Citadel II.

  • Garrus
  • EDI

5

Priority: Eden Prime

You can do this operation at any time. In fact, it is DLC in the original version of the game, but you still probably want to complete it early as it gives you a new squadmate.

6

Citadel Missions And Conversations

At this point, it's smart to head to the Citadel and talk with all of the people listed on your map.

7

Citadel: Hanar Diplomat

Complete while you're visiting the Citadel.

8

Aria: Blood Pack / Aria: Blue Suns / Aria: Eclipse

Complete while you're visiting the Citadel.

9

Priority: Sur'Kesh (Meet The Diplomats)

By doing this quest, you unlock the Krogan DMZ cluster, which can be useful for the next quest.

  • Garrus
  • Liara

10

Scanning Missions

As you were walking around the Citadel, you likely acquired several missions that tasked you with getting things from certain planets. Many of these quests are progress-sensitive, so now is a good time to travel to the different systems and do some scanning. Beware that Bioware decided to make things confusing by allowing you to pick up quests before you can actually do them. For instance, Citadel: Heating Unit Stabilizers and Irune: Book of Plenix can't be completed at this point.

11

N7: Cerberus Attack

It doesn't really matter when you do this one.

12

Attican Traverse: Krogan Team

If Wrex is alive and gives you this mission, then it makes sense that Shepard would do it before the one Victus gives. The Krogan is a good friend, after all.

  • Javik
  • Garrus

13

N7: Cerberus Abductions

A nice way to break up the two major quests.

14

Tuchanka: Turian Platoon

Do this before Priority: Tuchanka, so the most significant mission can end Act One. It must be done before Priority: Thessia.

  • Garrus

15

Tuchanka: Bomb

This is basically part two of the last operation. You need to complete it within three quests of the previous one, or else you'll automatically fail.

16

Trip To The Citadel

Before embarking on the final quest of Act One, you need to head to the Citadel and deliver the items you found from scanning. Everyone you need to see will be labeled on your map. While here, go to the requisitions terminal in the Spectre office, as it'll allow you to buy any quest items you've missed. You can tell which things are quest-related because they won't be weapons or armor.

17

Priority: Tuchanka

The final mission of the Act, which includes plenty of important choices.

  • Javik
  • Liara

ACT 2: The Geth And Quarian Conflict

Mass Effect 3 Tali and Legion standing together, close up

During the second act of the game, Shepard finds themself in the middle of the strife between the Quarians and the Geth. It's up to you how their long-running conflict finally ends.

You can start a romance with a companion during this act.

Optimal Mission Order:

Order

Mission

Notes

Recommended Companions

DLC

1

N7: Cerberus Fighter Base

A nice way to begin the Act is with a simple N7 mission.

2

Priority: The Citadel II

At this point, besides scanning planets, there's not much you can do before completing this major quest. Afterwards, warn Miranda about Kai Leng.

  • Javik
  • Garrus

3

Citadel Missions And Conversations

Head to the Citadel as there are many new conversations to have and missions to pick up. Complete any of the quests that take place on the station before leaving. And as always, just try to speak with everyone listed on the map.

4

Kallini: Ardat-Yakshi Monastery (aka Mesana: Distress Signal)

This is one of those quests that can be done at any time. But this is a good opportunity to play it before you're amid the Quarian and Geth drama.

  • Liara

5

Citadel: Aria T'Loak

Once you start this mission, you can't return to the Normandy until you've finished. Go ahead and start this one now, as it doesn't make narrative sense for Shepard to embark on this operation while the Geth and Quarians are at each other's throats.

Omega

6

Arrae: Ex-Cerberus Scientists

It doesn't really matter when you do this quest, but before meeting the Quarians seems sensible.

  • Kaidan/Ashley
  • EDI

7

Priority: Perseus Veil

It's time to meet with the Quarians.

8

Priority: Geth Dreadnought

The Perseus Veil mission naturally leads into this one. So, it makes sense to do this quest next. If you want to romance Tali, start her romance before going on this mission

  • Garrus (if romanced)
  • If you are romancing Tali in this game but had a different romance partner in Mass Effect 1, bring that romance partner

9

N7: Fuel Reactors

Give yourself a little break from heavy story missions to do this secondary one.

10

Rannoch: Admiral Koris

This and the Geth Fighter Squadrons operations should be done before Priority: Rannoch because they both help you achieve the best ending for that quest.

  • Tali
  • EDI

11

Rannoch: Geth Fighter Squadrons

  • Tali

12

Scanning Missions

After visiting the Citadel earlier, your journal is probably filled with quests that require you to scan planets. This is a good opportunity to do most of them. However, you'll not be able to complete Dekuuna: Code of the Ancients, Hades Nexus: Obelisk of Karza, Hades Nexus: Prothean Sphere, or Silean Nebula: Rings of Alune at this time.

13

Trip To The Citadel

Return to the Citadel and speak to everyone, specifically those who you've got items to give, and have another look at the Spectre requisitions terminal to purchase any quest items you've missed.

14

Priority: Rannoch

A significant mission that brings the Act to a close. To pass the final conversation check, the following must be true:

  • Tali is alive and loyal
  • Legion is alive and loyal
  • Tali was not exiled
  • You passed the check between Tali and Legion in their argument during Mass Effect 2
  • Rannoch: Geth Fighter Squadrons is complete
  • You saved Koris
  • You have four bars of Reputation

ACT 3: Asari And Cerberus

Mass Effect 3 Kai Leng On Thessia extending arm

Various things happen in Act Three, such as the Asari joining the war effort and Cerberus continuing to cause problems. There are not many secondary missions in this section of the game as things start to build towards the climax.

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Optimal Mission Order:

Order

Mission

Notes

Recommended Companions

DLC

1

Scanning Missions

If you've still got any quests that require you to scan planets - such as the ones that you couldn't do earlier - then this is the time to do them. You'll soon get the opportunity to turn them in.

2

Priority: The Citadel III

The Leviathan and Shore Leave missions should be saved for later, so this one is pretty much your only option at this time.

3

Citadel Missions And Conversations

As you'll already be on the Citadel during this period, you might as well do the usual routine of speaking with everyone and turning in missions.

4

Priority: Thessia

This quest is the only option as you still want to save the other ones for later.

  • Javik
  • Liara

5

N7: Communication Hub

After the mission on Thessia, this last N7 operation unlocks, and you should do it straight away.

6

Priority: Horizon

To get the "best" result at the end of this mission, the following must be true:

  • You've spoken to Miranda three times
  • You warned Miranada about Kai Leng
  • You gave Miranda Alliance resources

7

Citadel: Dr. Bryson

It's good to do it this late as it reveals a lot about the Reapers, which feels fitting as shortly you'll be bringing them down.

Leviathan

8

Mahavid: Leviathan

  • Your romance partner

Leviathan

9

Namakli: Leviathan

Leviathan

10

Despoina: Leviathan

  • Your romance partner

Leviathan

11

Citadel: Shore Leave

This is the final quest you should do before the point of no return. The whole thing serves as a goodbye to your squadmates, so you don't want to do it earlier. Plus, the Normandy crew going on shore leave to reset before embarking on their greatest mission is a logical move.

Citadel

12

Silver Coast Casino: Infiltration

  • Your romance partner
  • Wrex
  • Javik

Citadel

13

Citadel Archives: Escape

  • EDI
  • Wrex

Citadel

14

Citadel Docks: Retake the Normandy

  • Wrex
  • Ashley/Kaidan

Citadel

15

Citadel: Party

Citadel

Endgame

Shepard worn out And Catalyst glowing blue and white in Mass Effect 3.

In the last two missions of the game, you attempt to stop Cerberus and the Reapers for good.

Optimal Mission Order:

Order

Mission

Notes

Recommended Companions

DLC

1

Priority: Cerberus Headquarters

This operation serves as the point of no return in the game. You won't be able to do any more side missions after you decide to attack Cerberus. So, make sure you've done everything else beforehand. This is a good time to sweep up the last of your side quests and buy the best gear you can afford!

2

Priority: Earth

This is the final mission in the game and of the entire trilogy. In it, Shepard finally takes on the Reapers, and some of your squadmates could die, so be sure to read our guide and check how to keep your favorites alive.

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