These achievements will be unlocked as you play through the main story. There are 27 missions, but only 9 related achievements.

Enjoy Your Homecoming
Complete Story Mission: Welcome Home.


What a Disaster
Complete Story Mission: A Terrible Reaction


Take That, You Pipeline Jerks
Disable the FOW in Insula Fonte.


F!#& YOU, MISSILE
Complete Story Mission: Missile Cowboy.


The Power of Bavarium
Complete Story Mission: A Long and Dangerous Road.


Finally on the Offensive
Complete Story Mission: Tangled Up In Blue.


These Mines are the Pits
Complete Story Mission: The Great Escape.


Mistakes and Triumphs
Complete Story Mission: The Shatterer of Worlds.


Son of Medici
Complete Story Mission: Son of Medici.

These are pretty straightforward. Anything you destroy will build up your chaos. The milestones are 1000, 100,000 and 1,000,000.

(Just) Causin' Chaos
Get 1000 Chaos.


Chaos Is My Middle Name
Get 100000 Chaos.


Chaos Millionaire
Get 1000000 Chaos.


This one seems to noticeably unlock after the 1,000,000 mark. If it doesn't unlock immediately, just get a little more chaos and you'll get it eventually.

Getting it in Gear
Earn at least 3 Gears in a Challenge.


This one is easy. Just play any challenge and get at least 3 of the 5 gears. Pretty easy to get AT LEAST 3 stars in any challenge.

You've Got Gear
Earn 5 Gears in a Challenge.


This one also isn't too bad, since there is at least one challenge that you can do really easily.

Bragging Rights
Beat another player's score in a Challenge.


Depending on your friends list, you'll probably get this one easily. Otherwise, checking around the forum for a player willing to add you as a friend could be an option. Just have them get a low-ish score, then beat it.

A Real Gear-Getter
Earn at least 3 Gears in one Challenge of every type.


There are 8 types of challenge: Destruction, Explosives, Weapon, Tether, Traversal, Land Vehicle, Air Vehicle and Sea Vehicle mods. You need at least 3 gears in one challenge of each related type.

All the Gears
Earn 5 Gears in every Challenge.


This one will take you a while. Some of the challenges can be tricky and may require you to unlock some of the related gear mods in order to get up to the full 5 gears. Most of the challenges were okay for me, but there was about one challenge of each type that was particularly difficult.

MOD Initiate
Unlock your first GEAR MOD and activate it.


You'll probably unlock this one after 1 challenge. Make sure you toggle it on once it's unlocked.

MOD Specialist
Unlock every GEAR MOD in a single category.


Unlock gear mods by completing challenges for the appropriate type. There are 8 types of challenge. The fastest to complete for this achievement may be the tether type, since there are only 4 challenges for this, and only 15 gears required for all mods unlocked.

MOD Tinkerer
Have every GEAR MOD active for at least 1 minute each.


Once unlocked, a gear mod can be toggled on and off. Simply have each mod toggled on for at least 1 minute each. The easiest way to confirm is to toggle every mod on at once and wait around for a minute.

Earth, Wind and Sea
Unlock Rebel Drops for at least one land vehicle, one air vehicle, and one sea vehicle.


Rebel Drops are unlocked either by bringing vehicles to garages in towns, or by liberating military settlements.

Unlocked and Fully Loaded
Unlock every weapon and vehicle available in the Rebel Drop menu.


Same dealio here. Unlock vehicles using garages and unlock vehicles and weapons by liberating settlements.
See 'Caught 'Em All!' achievement for further tips on vehicles.

Feat Fetish
Perform every Feat.


You can check which feats you have not completed by looking at Feats in the Leaderboards menu. The one you may have the most trouble with is the Distance travelled in Soap Box Car, if you don't know what that is.

insert guide for this here

Can't Touch This
Call-Out another player in a Feat.


In the Feat area of the Leaderboards menu you can click on specific feats. Click one and choose the option to call-out a friend. I'm not sure whether you need a friend to actually own Just Cause 3, so you might be able to just call-out anyone.

Anything You Can Do...
Beat a score you were Called-Out on.


The receiving end of the previous achievement. You probably need to specially get a friend to help you on this one, unless you have very competitive friends. Have them call you out on an easy feat, before either of you have too high a score on it.

Vive la Revolution
Liberate a Province.


This could be in the story section, since you have to do a fair amount of liberating to progress the story. In any case, you will do this.

Baker's Dozen
Liberate 13 Settlements.


You'll get this one pretty early on too. As I said, you have to liberate quite a few provinces, and there can be up to 6 settlements in a province.

Hope Springs Eternal
Completely liberate Insula Fonte.


This is the island you play on in Act I, in the south-east.

Taming the Dracon
Completely liberate Insula Dracon.


This is in the south-west. You play on it for the majority of Act II.

Heart of Stone
Completely liberate Insula Striate.


This is essentially the rest of the map from the first two achievements. This is where you play Act III of the story.

First Encounter
Successfully complete an Encounter.


You do an encounter as part of a story mission, but that one does not count for this achievements. It's pretty easy to find an encounter out in the world, so you shouldn't have issues with this one.

Three Holy Hideaways
Unlock 3 Heat-Clearing Priests by completing Encounters.


You can very often find an encounter near an empty monastery which, when completed, will make the monastery usable to clear your heat level.

Supply and Demand
Unlock 10 Resupply Points by completing Encounters.


Some encounters will unlock resupply points. Getting these encounters are pretty much just chance. This was my second-last achievment and I just spent a while wingsuiting around hoping for encounters. Check in and around towns.
These are often more civilian oriented. Things such as towing to a gas station or delivering a vehicle.

No Stone Unturned
Find every collectible strewn across Medici.


You can see the progress of all your collectibles in the Progress menu. Collectibles appear on the map as a circle with a question mark inside, but only in provinces that you have fully liberated.

Remember the Fallen
Light a candle at every Rebel Shrine.


Shrines are small wooden structures with candles inside. They are often found near monasteries, light houses and other relatively outlying locations.

Caught 'Em All!
Collect every vehicle available by bringing them to Mario's Garages.


For this one, you're going to want to unlock the gear mod that highlights vehicles that you have not collected. It's the second mod in the Land Vehicle type.

Diary of the Madman
Discover all of Di Ravello's audio tapes.


These are small audio tapes, believe it or not. They are often found in towns.

Old School Cool
Find every vintage weapon and vehicle part.


These look like dirt piles with a shovel stuck in it. These are often found in non-populated areas and outlying islands.

Tomb Raider
Pay your respects at every Ancient Tomb.


There are no Tombs on the two south islands, they're all on the big one. Press E to pay respects.

Consummate Daredevil
Drive a land vehicle off of every Daredevil Jump in Medici.


Instead of the question mark icon, daredevil jumps are marked by a white motorbike symbol.

These two achievements require the destruction of objects in military bases. If you have liberated all bases already, you have to go to the map, click and a base and choose to re-oppress it. You have to have finished the game to have this option.

This was Supposed to be a Western
Destroy all Chaos Objects in a Base without leaving your vehicle.


This one might seem pretty tricky, since you have to attack a military base with its SAMs and helicopter support and aerial support and AA guns. All of that.

However, when I did this, the helicopter I started with was destroyed. I switched to another helicopter of the same type and was able to get this achievement, so just make sure you don't destroy any chaos objects while you are outside the same vehicle.

...Without Bullets!
Destroy every Chaos Object in a Military Base without weapons, grenades, or planted explosives.

This one is pretty simple. Just use solely grapple hook tethers to destroy all chaos objects in a military base. You can upgrade the strength of the tethers by completing tether challenges and unlocking related gear mods. As stated in the description, it must be a military base, not an outpost or something.

My Little Rocket Man
Tether an enemy to a launched gas cannister. Adeo, amico!


This one isn't too hard. You can shoot a canister and have a short window to grapple an enemy before it launches, or you could just grapple the enemy first.
Keep in mind that some enemies can remove the grapple from themselves, so use a weak enemy if you can.

You're Outta Here!
Plant a Booster Explosive on an enemy soldier. Then send them flying.


Booster Explosives are an unlockable gear mod in the destruction type. Once active, throw one of your explosives on an enemy. From my experience, you don't even need to activate it, only place it.

Top of the World
Stand on foot at the highest point of Medici.


The large snowy mountain is pretty easy to see from pretty much anywhere on the map. There is a small stone structure at the highest point, so just wingsuit/parachute/fly up there and stand on that structure.

Forgive Me, Father...
Take sanctuary in a monastery to clear Heat Level 5.


Complete encounters to unlock a priest. A monastery can be used if it is coloured blue on the map.
The easiest way to get Heat Level 5 is to take a helicopter into a town and shoot up the police station and other military assets and personnel. You want to make sure a monastery is close-by, otherwise you may lose you heat level on the way by breaking line of sight.

Winner Takes All, Again
100% Just Cause 3.


Complete collectibles and challenges. Progress can be checked by going to the Progress menu. How about that.
The DLC adds challenges and collectibles, but they are not required for this achievement. You only need to get and do everything in the base game.

Break a Leg!
Defeat the "Old Friend" (Boss at the end of "Taking Control").


You'll get this as you progress through the story arc. Basically, when you reach it, just shoot at each of the legs. Rocket launchers work pretty well.

My Name is Eden
Beat the last mission of the Sky Fortress Expansion and complete the story arc.


Just beat the story yo.

Like a Fish... in the Air!
Use the Bavarium Wingsuit to take off from water.


Once you've unlocked the Bavarium Wingsuit (starting the first mission in the expansion), find some water. From the water, hold the button usually used to open the wing suit (E on keyboard by default).

Quite the Connoisseur
Earn at least 1 Gear in all Challenges of the Sky Fortress Expansion.


There are a total of 4 challenges in this expansion and they are progressively unlocked as you complete story missions. Three of the challenges are using the wingsuit to fly through wings ( like the base game challenges) and one is defeating a bunch of drones using the mounted weapons on the Bavarium Wingsuit. Pretty easy to get 1 gear in each challenge.

A True Master
Earn 5 Gears in all Challenges of the Sky Fortress Expansion.


I didn't have too much trouble with these challenges. Hardest was probably the first of the wingsuit challenges (they're numbered).
I had some trouble with the drone one, because my wingsuit rocket wasn't locking on to them. If you have this issue, disable the precision aim gear mod before trying again. You may have to restart the game.

Look at the Sly Fox
Use the Barrel Roll to evade 10 incoming missiles.


Perform a barrel roll while using your wingsuit by moving in a direction and pressing the barrel roll button (ALT on the keyboard by default). You'll be given a warning of incoming missiles telling you when to evade.

Stock-Keeping
Defeat 1 of each Drone type.


I never needed to go for this one. You should just get it as you play.

One Mech of a Ride
Hijack your first Mech.


Pretty sure you'll do this as you go through the story.

One Last Score
Beat the last mission of the Bavarium Sea Heist expansion and complete the story arc.


Self-explanatory. There are only a few missions.

Certified eDEN Mech Operator
Earn at least 1 Gear in all Challenges of the Mech Land Assault Expansion.


There are only 2 challenges in this expansion, both of which are wave-based survival challenges.

eDEN Employee of the Year
Earn 5 Gears in all Challenges of the Mech Land Assault Expansion.


You can score extra points in these challenges by throwing enemies, throwing things at enemies and using the Mech's Force Pulse (default MMB). There is also a time bonus where you earn more points the faster you beat a wave.
In the challenge consisting of just vehicles, I beat it only using the gun (minimum points from each enemy).
The other challenge, consisting of vehicles, soldiers and paratroopers, took a few attempts. Try to refrain from using the gun to kill almost anything. Throw drones into each other, hit paratroopers with shipping containers once they've landed and use the Force Pulse on the soliders when the park their trucks and get out. And remember you can shoot the plane the paratroopers come in on!

This Is Not A Fireball
Destroy 30 enemy vehicles using the Mech's Force Pulse.


You'll learn about the Force Pulse as you play through the story. You can farm this one in the challenges if required. The middle mouse button is the KB+M default.

Free Birds
Liberate 3 Detention Camps.


A new island in the north is added to the map in this expansion. You'll find detention camps in settlements around the island. I think there are more than 3 in total.

I Should Buy A Boat
Get the Rocket Boat, also known as "The Loochador".


You'll get this after the first mission in the expansion.

One Last Score
Beat the last mission of the Bavarium Sea Heist expansion and complete the story arc.


Beat all the story missions, need to liberate a bunch of structures over the ocean.

Loochador Master
Defeat 5 enemy helicopters with the Rocket Boat.


Once you've unlocked the weapons for the boat by completing story missions, simply destroy 5 helicopters with it. The missiles can lock onto enemies, so it's not too hard.

The Flying Medician
Defeat 10 enemy vehicles while in the air with the Rocket Boat.


Ensure you have enabled the gear mod that enables the jump ability on sea vehicles. When you lock onto enemy vehicles, spam missiles at it, then boost jump before it gets destroyed. As long as you are in the air when the vehicle gets destroyed, it counts.

Lightning Bolt!
Defeat 1 enemy helicopter using the eDEN Spark.


Easy. You get the eDEN Spark near the end of the last mission. You have unlimited ammo for it, since it recharges over time. You'll see a helicopter as soon as you get outside after getting the Spark.

Staying Power
Defeat 10 enemies with the same eDEN Spark strike.


I got this right after getting the weapon. There is a group of over 10 enemies as soon as you get outside. Once you've started the strike, it moves slowly when you try to move it.