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Mass Effect 3 Mission Order: best sequence for all priority, DLC and side quests

by Alex Donaldson on 24 May, 2021

Due to the very nature of its storyline, Mass Effect 3 is without a doubt the most linear of the original Mass Effect trilogy - but there's still a bit of freedom in how and when you tackle its missions, which can only mean one thing... Like with its predecessors, we have thoughts on the optimum mission order for Mass Effect 3.

Interestingly, this mission order differs from our suggested ME1 Mission Order and optimum ME2 Mission Order in one key way - and that's that there are a few missions in ME3 where if you don't complete them at the right time, you can have major negative consequences for classic beloved characters. ME3 is a sprawling game that takes into account lots of the choices and consequences from across the trilogy, too - so some of your options will be based on your actions in the previous games.

In this guide, we naturally offer up our suggested mission order for ME3 to give the best story flow throughout - though as always, remember that this is only a suggestion - go with your gut!

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Mass Effect 3 Mission Order: the best sequence to take with Priority, DLC and Side Quests

Generally speaking, a good rule of thumb for the Mass Effect 3 mission order is this: any missions marked 'Priority' are not actually a priority. Priority Missions are major story missions, and therefore never expire. However, several of the side quests you get are time limited, and often advancing the next Priority Mission in the chain can close and lock off already open or as-yet unfound side quests.

So: scan planets, visit the Citadel, and talk to everybody you can in between each and every Priority Mission. Exhaust all options - then do the next priority quest.

Beyond that, we also have some broad suggestions in this guide on the order in which you should tackle ME3's various stories. Especially for DLC, some missions that unlock right from the start of the game, or halfway through, are best suited to be saved until the very end. Because of the sheer size of ME3 and number of points, we've broken the game into 3 acts, separated by the 3 major 'state-changing' events that happen on the Citadel every so often.

Your choice of squad mates won't impact mission progression, but some of your friends have more interesting things to say on some missions than others. If you want help picking who to take on each mission, check our guide on the best squad for each mission in ME3.

The only other thing to mention is War Assets, the currency that helps to determine what ending you get in Mass Effect 3. All of this is detailed in full in our ME3 endings guide, but the short version is this: your war assets determine how many of ME3's ending choices you'll have.This varies depending on version; around 3100 Effective Military Strength will do in the original extended cut version. In Legendary Edition you'll need around 8000 of the Total Military Strength stat that version has instead instead..

Mass Effect 3 Mission Order - Part 1

  1. Prologue: Earth, Priority: Mars, and Priority: The Citadel I: these three missions will follow sequentially at the very start of the game. Simply play them one after the other to be introduced to the basic concepts of Mass Effect 3, including how it differs from its predecessors. There's some small notes about this trio of missions:
    • The tone you take with Ashley or Kaiden (whoever is alive) on Mars will impact their attitude later in the game - if you reassure them with Paragon prompts, they will be more likely to trust you later. If you choose Intimidate, they will be distrusting of you, which can have grave consequences later.
    • When talking to The Illusive Man, you should use the investigate conversation option and then use Charm/Paragon or Intimidate/Renegade dialogue options - this can help to open up some things later on.
    • On board the Citadel, you'll be able to recruit friends old and new like Doctors Chakwas and Michel to join the Normandy. Visit everything. You can also recruit Dianna Allers, the reporter, if you wish.
  2. Priority: Palaven: head to Palaven to recruit a Turian Primarch, and an old friend, if they survived Mass Effect 2. You can slip in a planet scanning break before or after this mission if you wish.
  3. Priority: Eden Prime: this DLC mission unlocks Javik, the only DLC squad mate in ME3. This DLC is included in the Legendary Edition of the game. Despite being DLC, Javik is a fully-featured squad member and has many of the most interesting things to say in many missions of the game thanks to the unique direction he approaches things from. 
  4. Grissom Academy: Investigation: while this is a side quest, you must complete this quest soon after it first pops or else there will be negative consequences for characters you may like.
  5. N7: Cerberus Lab: this side mission unlocks as soon as you're done with Priority: The Citadel I and get back on the Normandy. Complete this quest, and be sure to loot thoroughly to get some weapon upgrades and a Failed Medi-Gel Experiment that's used in a side quest.
  6. Planet Scanning Break: at this point, take a little time out to go planet scanning in all the regions you can. Right now you should have access to several systems, and more open up regularly as you progress the game. Scanning clusters rewards quests, research items, credits, and war assets - the later of which can of course be vital for obtaining the best ending.
  7. Back to the Citadel: this isn't a Citadel quest, but rather us suggesting you use this time to catch up on things in the Citadel. You'll be able to meet up with a number of old friends, advancing personal stories with some consequences of your choices in previous games revealed. There's also shopping, and a number of side quests.
    • Probably the most important single thing to note is that you'll need to meet with Miranda three times to advance her story, if she survived with ME2 - so take your first meeting here, and keep taking them.
    • The Citadel: Hanar Diplomat mission appears in this time, and features a returning ME2 cast member where you learn more about the outcome of their loyalty mission. 
  8. Priority: Sur'kesh: on the planet of Sur'Kesh, try to bring the leaders of various nations to an agreement - and prevent hostilities. 
  9. Back to the Citadel again: this is an ideal time to just pop back to the Citadel and continue conversations and side quests
  10. Tuchanka: Turian Platoon: help a Turian squad that's crash-landed on Tuchanka.
  11. Tuchanka: Bomb: it's vital you tackle this mission quickly, as failing to do so can have grave consequences later in the game.
  12. Attican Traverse: Krogan Team: help a team of Krogan, and make a major choice around the fate of an old friend or foe from ME1. Also, enjoy the return of an ME2 favorite, if they're alive.
  13. N7 Side Quest Time: there's a few N7 side quests you can grab here, all with the usual mix of combat, goodies to grab, and so on:
    • N7: Cerberus Abductions
    • N7: Cerberus Attack
  14. Back to the Citadel once more: again, you should take this opportunity to return to the Citadel to talk to the various people you can there, browse shops, and complete side quests. This time it's more critical, as after your next priority mission, events on the Citadel will mean some quests there lock forever. Here's a few things you should complete:
    • Crew interactions: chatting to Garrus, Vega, Joker, EDI, and Liara aboard the Citadel
    • Old friends: interactions with Kelly Chambers, Thane, and Miranda (if they're available)
    • Side quests: any Citadel quests in your journal, if you can
    • Recruitment: getting a ship's doctor to join, Chakwas or Michel
    • Spectre Terminal: authorize any actions from the terminal that you can
  15. Priority: Tuchanka: participate in one of the most momentous missions in the entire Mass Effect trilogy, with many major decisions to make - and with a lot of those decisions dependent on what actions you took in the previous two games, particularly in ME2.
  16. Planet Scanning: this is entirely optional, as you can save it for a mission or two, but a bunch of new systems will be available, so you should go scanning to get more war assets, research, and credits. 
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Mass Effect 3 Mission Order: Part 2

  1. Priority: Citadel II: after completing the major mission on Tuchanka, you'll undertake another major mission, this time on the Citadel. As soon as you land on the Citadel next, this will trigger.
  2. Citadel Casual Times: after Priority: Citadel II, you can spend time on the Citadel again... and because much has changed, you'll be able to find new side quests, missions, and characters to talk to. This includes side quests like:
    • Citadel: Volus Ambassador or Arrae: Ex-Cerberus Scientists: ME2 character cameo
  3. Planet Scanning: Even more planets open up now, so once you leave the Citadel, go tick a few more systems off your list.
  4. Side Quest Bonanza:
    • N7: Cerberus Fighter Base
    • N7: Cerberus Scientists
  5. Mesana: Distress Signal / Kallini: Ardat-Yakshi Monastery: features an ME2 cast member appearance, if they're alive.
  6. Character Interaction Downtime: now is an ideal time to return to the Citadel and hang out with all your friends a little. At this point, a lot of them will have new things to say.
  7. Omega DLC / Citadel: Aria T'Loak: this is a DLC mission, and it's a bit different from the others in the game in that it's a multi-mission strand that takes you away from your ship and crew. Once you start it, there's no going back to the Normandy until the whole significant quest is complete, so keep that in mind.
  8. Priority: Perseus Veil: it's now the turn of the Quarians and Geth to have their moment in the ME2 spotlight. If she's alive, Tali will of course be present.
  9. Priority: Geth Dreadnought: next up, infiltrate a Geth Dreadnought as a favor to the Quarian fleet.
  10. Citadel Catch-Up: head back to ME3's main hub once again to talk shop, actually shop, complete side quests, and generally advance its many side stories.
  11. Rannoch: Admiral Koris: for the maximum options in the near future, you'll want to make sure the Admiral is rescued, no matter how much he protests. 
  12. Rannoch: Geth Fighter Squadrons: complete this mission before triggering the main Rannoch quest, as it will have an impact.
  13. Priority: Rannoch: all those Geth and Quarian missions have been leading to this - plus two games' worth of back-and-forth lore between the two races. To unlock the best result, you must satisfy several conditions across multiple games:
  14. Planet Scanning & Side Quests: use this opportunity to scan any planets and systems you need to, or to complete any side missions you skipped over earlier. 
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Mass Effect 3 Mission Order: Part 3

  1. Priority: The Citadel III: its back to the Citadel for the third in the Citadel Priority trilogy; the events here are much less earth-shattering - unless you betrayed an old friend, and then things get really messy...
  2. Priority: Thessia: this mission takes you to the Asari homeworld. Combat be damned, the absolute best squad mate combination for this mission is Javik and Liara; take them with you. They have an explosive fight on the Normandy afterwards.
  3. N7: Communication Hub: this side quest opens up as soon as Thessia is completed; it's not the most exciting, but it is what it is.
  4. Planet Scanning again: after Thessia, more systems await to be scanned. It's a handful, but there's War Assets, Credits & Research to be had.
  5. Priority: Horizon: head back to a familiar planet for a major story quest. For the best outcome here, you need to make sure you talk to Miranda multiple times on the Citadel prior to this, give her access to Alliance resources when she asks, and warn her about Kai Leng in dialogue choices.
  6. Citadel: Dr. Bryson / Leviathan: this quest will have been waiting for you most of the game; it's another multi-part DLC, like the Omega quest. We've saved it for here since it delivers major story revelations about ME3 and the wider Mass Effect story at large. It unlocks a range of new star systems you should scan in full for resources, and enjoy this major story beat that really shouldn't have been made into a downloadable add-on. 
  7. Citadel: Shore Leave: you can place this DLC in one of two places; either here, or you can load up an post-game save after experiencing the ending of the game and do it then as a sort of non-canon coda. It's a goodbye to the characters of the Mass Effect trilogy. It's best to do it here rather than earlier in the game, however, as all of your old squad mates and friends will only appear if you've completed their missions in ME3. Everyone you know that is alive can appear, and in addition you can use features like the Arena and Arcade to farm cash and weapon upgrades. Do everything you can here and enjoy the story, even if kicking back feels a little wrong in the middle of a war.
  8. Priority: Cerberus Headquarters: this is the point of no return. After you initiate this mission, it's a rollercoaster to the end.
  9. Priority: Earth: this is it. (Isn't it?) For more advice on this section of the game, check out our full & comprehensive Mass Effect 3 Endings guide.