Full list of all 93 Assassin's Creed Odyssey achievements. It takes around 80-100 hours to unlock all of the achievements in the base game on Windows.
The base game contains 50 achievements, and there are 5 DLC packs containing 43 achievements.
Complete Xenia's questline.
Complete all underwater location objectives.
Complete 20 Quests on Pephka, Obsidian and Abantis islands.
Defeat Medusa.
Unveil all sub-regions of Greece.
Defeat the Minotaur.
Defeat the Cyclops.
Defeat all the Cultists of Kosmos.
Upgrade your Spear to Tier 6.
Complete the Daughters of Artemis questline.
Complete Episode 9 + Epilogue.
Complete Episode 8.
Complete the Hippokrates questline.
Complete Episode 7.
Perform an Overpower Attack with every weapon type.
Become the first Mercenary.
Outwit the Sphinx.
Complete the Olympic questline.
Upgrade the Adrestia to Legendary Status.
Defeat a Mercenary in the Arena.
Become Champion of the Arena.
Acquire a Tier 3 active Ability.
Discover Atlantis and speak with Pythagoras.
Complete Markos's questline.
Reach Level 50.
Complete Episode 6.
Complete Episode 5.
Raise your Bounty to the maximum level.
Cleave a ship while having an all-women crew.
Recover the Cyclops's eye from a goat on Kephallonia.
Defeat a full cluster of Cultists of Kosmos.
Equip a Legendary Armor set.
Equip 1 Legendary melee weapon and 5 Legendary armor pieces.
Complete Episode 4.
Complete 20 Bounties, War Contracts, or Naval Quests from Message Boards.
Engrave a Legendary Item with a Legendary Effect.
Fully crew the Adrestia with Legendary Lieutenants.
Sink your first Epic Ship.
Complete Episode 3.
Win your first on land conquest battle in any region (excluding Megaris in Hero's Journey).
Kill the Leader of any Region with Low Resources, other than Megaris.
Cleave a ship in half.
Complete Episode 2.
Spend the night with another character.
Recruit and assign a Legendary NPC for your ship.
Acquire and equip your first Legendary item.
Complete Episode 1.
Upgrade the Adrestia for the first time.
Engrave your first item.
Complete the Battle of 300.
Heal by getting 10 headshot kills while you have the Golden Harbinger equipped.
Acquire the Sword of Kings
Secure your bloodline
Kill all the Ancients in the Order of Dominion in Messenia
Heal by parrying 10 times with the Judgment of the Lion.
Continue the bloodline.
Kill all of the Ancients in the Order of the Storm in Achaia.
Kill 10 enemies using the Rapid Fire ability.
Land a Rush Assassinate that chains 4 times with the Blade of the Lion
Discover the truth about Darius' past
Kill all the Ancients in the Order of the Hunters in Makedonia
Kill the Makedonian Lion
Kill 10 enemies using the Fury of the Bloodline Ability.
Set 10 enemy ships on fire.
Kill 10 enemies using the Death Veil ability
Complete The Heir of Memories
Complete Every Story Has an Ending
Complete A Friend Worth Dying For
Complete The Daughters of Lalaia
Complete One Really, Really Bad Day
Complete Divine Intervention.
Complete The Show Must Go On.
Complete The Image of Faith
Complete Old Flames Burn Brighter
Complete A Poet's Legacy.
Complete A Brother's Seduction
Defeat the Hekatonchires.
Forge the 3 Legendary Weapons.
Collect all the Keeper's Insights in Episode 3.
Completely fill the Knowledge Sequence.
Kill 10 Isu Soldiers with the Blessing of Kronos enhancement.
Dethrone the king.
Defeat all of the Fallen.
Close all Tartaros Rifts.
Collect all the Keeper's Insights in Episode 2.
Defeat Cerberos.
Win the conquest of Elysium with freed humans from the 3 main regions.
Remember who you are.
Destroy all of the Marble Maiden Tributes.
Kill all Overseers in Elysium.
Collect all the Keeper's Insights in Episode 1.
Defeat Steropes the Lightning Bringer.
Defeat Arges, the Bright One