Just Cause 3

If like me you've left this until the end of the game, You'll realise it's a bit frustrating trying to spawn these encounters.

What I have managed to figure out is that there are semi random events in the four following areas but eventually you will get a delivery one or whatever you need for a supply drop to be unlocked.

1 Surpicco Town in Plagia this location will have a plane delivery drop up at the airport on the hill and a vehicle delivery between two little houses on a main road to the north of the town. If you just fast travel in and out and wait a while a marker will unlock anyway, guiding you to whichever encounter has spawned. You may need to fast travel again if it's the wrong one, for me a new one spawned after a minute or two.

2 Griphon base in Costa Sud. This place has a juggernaut delivery halfway down towards the lower entrance to the base, also up top a helicopter drop will spawn from here, I must stress you need to wing suit around and possibly fast travel in and out but make sure you wait around for more than just a minute or so just give it a little time and wing suit around if you can't see anything happening.

3 Sancte Lucas in Lavanda, just outside the monastery/church here a vehicle delivery will spawn eventually. Took me a while to get this one.

4 Salrosa sprint in Baia, at the maker for the challenge there will be a helicopter smuggler run.

These are just some locations I found in addition to using the guides above for assistance, I had a few of the gas station ones done at this point, so if you have those already like I did my guide should help you mop up any pesky ones that you cant find by town hopping looking for gas stations.

Please don't vote negative just because your pissed off at the achievement. Like others have said this is mostly semi random and a pain in the ass of an achievement. It may take a while to get the right encounter but keeping going back to the location and wait for another encounter eventually it will be the right one.

I wanted to provide some additional details to this achievement.

For anyone wondering, Encounters are random activities that pop-up while you are traveling through Medici. They are highlighted by small white circles that pop up on your HUD, telling you were to go.

The Encounters you will be looking for are anything that inlvolves delivering a vehicle or crate including :
Vehicle Delivery
Smugglers Run
Buggy Delivery
Out Of Gas
Juggernaut
Slippery Slope (bike delivery)
Crate Delivery

And some others I might have missed. I recommend going for them as soon as possible in your game so you wont have to go looking for them later. (don't do the same mistake I did and save it up for last)
There are some areas which are more likely to spawn these encounters like gas stations. You might also want to try to follow some YouTube videos of people finding these encounters though you wont be certain that they will spawn at the same place for you since they are random.
You can go for this at a 100% liberatation which could even be the best option since you wont be having trouble with authorities.

It took ages until I got this achievement (unfortunately it did not unlock on my 100% playthrough so I had to get the ten encounters twice!) and I really recommend to do this while completing the base game or searching for collectables.

Now the important part. The following list contains the coordinates where I found the random encounters. If you stay about 250m - 500m away from these coordinates the encounters should spawn after some time.

• N 38.536 E 42.342
• N 44.523 E 44.767
• N 43.951 E 41.602
• N 41.816 E 42.599
• N 42.479 E 44.144
• N 44.581 E 38.405
• N 37.096 E 38.995
• N 42.603 E 35.398
• N 43.829 E 40.259
• N 40.300 E 42.745

Sources I used:
https://steamcommunity.com/app/225540/discussions/0/48787656...
https://justcause.fandom.com/wiki/Random_Encounters

Just thought I'd add my own information along with the other two guides. One of them has a list of places you can try going while the other has a list of all the events that can unlock supply points.

So first of all, I noticed that this all has to be on the same save file. On my 100% run I already had 5 supply points unlocked. When I finished the game these Encounters were becoming a lot less common so I restarted. I was not able to unlock the achievement when I got 5 more, so these are not cumulative across saves.

To get this, I would recommend hanging out on the outskirts of different towns in different provinces. You don't necessarily have to have these settlements liberated, but it may help when the actual Encounter starts. You can get resupply points in oppressed zones, but again, it may be best to try and liberate them first. In most cases, if you already have a supply point in one province, don't try for a second one. There are some towns that when liberated already have a supply point, but I cannot remember off the top of my head which ones did. I would maybe take note of a new supply point's location once you've unlocked it.

One thing I noticed was that there were certain types of encounters that kept spawning in locations where I couldn't get a supply point/already had one. These encounters were ones that I called "moving encounters." Usually involving hijacking a vehicle of some kind and bringing it to a place. Getaway driver also counts as this. If you notice that "moving encounters" are the only ones popping up in a location, try somewhere else.

The encounters that you want to see are the "stationary" ones. Keep in mind, you can get these in provinces that already have a supply point. However, if you get a "stationary" encounter in a province that does not already have a supply point unlocked, this means that one of the encounters you need could spawn in this location instead, so fast travel away, do a mission, do anything else for about five minutes or so, then come back. The one I kept getting was called Stuck Gate. If you get a Stuck Gate encounter in a province without a supply point, for me it meant 100% of the time that one of the other encounters I needed could spawn there instead.

The theory composed above by the last two paragraphs I have yet to test out on multiple accounts. So if this turns out not being 100% accurate, I'll edit the solution or just outright delete it. But for me this worked. I did notice that gas stations had resupply boxes built into them, and after trying just hanging out at gas stations for about an hour, I had only gained one new supply point, so I don't think that's the best idea.