Patagonia Slope Runner Exploration Pack 18L – High Capacity Vest for Epic Days

Drew Thayer

The runner’s high-capacity vest for technical scrambles and long mountain days 

Patagonia may have engineered the ultimate high-capacity vest for hybrid running/scrambling activities and long running days in the mountains. There are a lot of great running vests that hold a little bit, and a lot of small backpacks that hold a lot, but very few of these backpacks are truly pleasant to run in. 

The Patagonia Slope Runner Exploration Pack is perfect for technical hybrid outings. It’s my favorite companion for running trails to scramble sandstone ridges in the Flatirons and Eldorado Canyon, where I’ll swap back and forth between trail runners and rock shoes.

Most of the time we’re either just running, or just hiking to do things, but sometimes we really want to run AND carry more than a few bars and a windbreaker. These are big and spirited outings that capture our imaginations: ridge linkups in the mountains in chilly conditions, trail-to-glacier loops, hut-to-hut running trips, and technical rock scrambles linked by singletrack.


Patagonia Slope Runner Exploration Pack 18L


For these activities, we’ve inevitably had to make a compromise to carry enough gear, which usually looks like running with a small backpack that swings around awkwardly as we run, dragging on our form like an anchor. It’s doable, but it doesn’t quite let us just simply run. Well that is over; we can now float over technical trails with 18 liters of capacity on our back, barely noticing that the load is there.

A running vest with enough structure to carry 5-10 lbs

Upon first impression, the Patagonia Slope Runner Exploration Pack appears to simply be a slightly beefier version of the Slope Runner Endurance Vest with the same flask-carrying front and a large rear pocket. In broad strokes this is true, but there are some very important differences.

The Slope Runner Endurance Vest is sewn like a piece of clothing, so it really feels like just another fabric layer on the torso that happens to include some pockets. As a result it’s the quietest, smoothest ride of any vest on the market, which is why I love it and have run some 1200 miles in mine over the past 2 years. 

Our for a run-to-scramble outing in the Flatirons with my Exploration Pack. It’s the perfect size to fit layers, rock shoes, chalk bag, food, and hydration for mixed-media aerobic activities like this, and really lets me enjoy the trail running since it carries the weight tight to my back like a vest.

The Slope Runner Exploration Pack is built to ride the same as the lighter Endurance Vest while holding substantially more weight, so it has a lot more structure. The chest straps and back are formed from a breathable waffle-pattern mesh that distributes weight well for a light material. In the back, a removable panel of semi-rigid, compact open-cell foam provides a lot of structure, despite being dramatically lightened by long strips of foam that have been removed. All things considered this panel only weighs 1.8 oz and really helps the pack carry weight, so I leave it in. 

One thing that makes the lighter Slope Runner Endurance Vest so comfortable is that the whole thing stretches, just like a piece of clothing. The larger Exploration Pack mesh material does not itself stretch, so elasticity around the torso is accomplished by elastic cord joining the shoulder straps to the main pack on the sides of the ribs in a cross-stitch pattern, a similar execution to Black Diamond’s Distance 15 pack.

This allows the pack to still hug your torso tight while it expands and contracts during vigorous breathing. While running in the Endurance Vest I typically forget that it’s there. The Exploration Pack doesn’t quite disappear like that, but it’s pretty darn close for a vest with the capacity of a small backpack. 

Believe it or not, this vest even has load-lifter straps! They are simple doubled-over elastic cords with a toggle, but they provide enough tension to keep the pack riding high and tight on the back.

Cruising along in my happy place on the continental divide near Jones Pass, with layer changes, snacks, and two 500 mL flasks of water in the Slope Runner Exploration Pack. This pack really rides like a vest, holding the load tight to the upper back and reducing swing and jostle to a minimum.

The capacity of a backpack, with some odd quirks

The reason to wear this vest is the 18 liter rear pocket. This is enough room to casually carry warm weather clothing like gloves, hat, and a light puffy – even a change of pants. It could easily hold layer changes and a lunch for a long on-the-move mountain day, or even a very minimal overnight kit (think bivvy sack and an ultralight down jacket) for an ambitious two-day aerobic mission. 

My personal favorite use of this vest is for solo running and technical scrambling on rock features where I want climbing shoes. The Exploration Pack has been the perfect tool for scrambling in the Flatirons above Boulder, Colorado. I can really run on the trails, unencumbered by any swinging or bouncing while the vest holds my rock shoes, chalk bag, and windbreaker etc. Then I can fit my running shoes in the pack and climb freely, not even noticing the vest, with a sip of water always available on the chest.

The slim design of this pack comes with a tradeoff of ease-of-use. You can see how large the heel of my Hoka Speedgoat trail shoe is compared to the mouth of the main pocket.

Everything that excels in a niche has a compromise, however. The tapered, lenticular shape of the volume pocket that lets this vest ride so well while running makes it kind of awkward as a backpack. Far from a simple open-top tube (like Black Diamond’s Distance pack, for example), this volume pocket has a tapered edge around the perimeter that is sort of hard to fill.

You need to pack it carefully, really pushing clothing into the edges to avoid a bulge in the center if you want the pack to lie flat against your back. This is all made more difficult by the fact that the mouth of this pocket is pretty small – smaller than the inside circumference of the pocket itself, which is unusual. I have to sneak my trail running shoes one at a time through the narrow opening and take a minute to get them placed where they need to be on the inside. 

A removable foam insert adds significant structure to the back of the pack. I’m hard pressed to find gear with such fine attention to detail as the weight reduction on this panel.

Carry soft flasks, trekking poles, and an ice ax

This vest carries three things well: soft flask bottles (and smaller items), trekking poles, and an ice ax, but not much beyond that. It’s not a backpack! But it performs its duties as a running vest quite well.  

The vest front itself is brilliant, a close clone of the Endurance Vest. The lightweight mesh chest pockets are each double-layered, with a long pocket that fits a soft flask or phone and a short pocket that fits things like energy bars, a buff, or lightweight gloves.

These pockets stretch to accommodate quite a lot of volume – even a fleece hat – yet cling tight to the chest, eliminating sway and jostle from heavy objects. I find this particularly important – I tested a Nathan vest once where the bottles swung around wildly as I ran, and the Black Diamond Distance pack has loose chest pockets that don’t grip a bottle tightly. I’ve dropped bottles accidentally while bending to tie my shoes several times; on one occasion a bottle slid down into a ravine! Tight pockets for the win.

Both of Patagonia’s running vests come with 500 mL Hydrapack soft flasks. These are great flasks, very durable and easy to clean. I prefer the simple nippled design and am fine without longer hoses; I can easily bend my mouth down to take a sip mid-stride. 

The pack has twin sleeves on the side of the volume pocket that hold folded trekking poles, and the elastic load-lifter cord doubles as a method to hold the poles tight if the pack is empty. There is also a very simple elastic piolet-style carry system that can carry a lightweight ice ax.

It’s a little bit finicky, but it’s extremely minimalist, which seems like a fair compromise since this isn’t really a backpack. In addition there are five extremely small thin webbing loops (i.e. smaller than your pinkie finger) on the back that could theoretically be used as lash points. Patagonia states that this vest can carry a helmet on the back, but it takes some creativity, like girth hitching one buckle to an elastic piolet strap and clipping the other to a webbing loop. Last, there is a small zippered pocket on the exterior side for organizing things like a wallet and your car key.

The front of this pack is a classic vest with tight mesh pockets that keep contents (phone, flasks, rolled up beanie) from bouncing. All the retention straps on this pack are executed in a very minimal fashion, keeping the pack slim and light. Note the flask nozzle retention loops and the elastic load-lifter straps.

A minimalist design keeps it pure for running 

Amongst a small family of crossover vest-like backpacks on the market, the Exploration Pack stands out as the only one that really rides like a vest while running. Close cousins include the Ultimate Direction Fastpack 20L, Black Diamond Distance 15L, and Nathan Crossover 15L. All three of these are built more like a traditional backpack, with a more usable rear volume pocket. Basically, these other options all work better as backpacks, and would be a more straightforward option for hiking. They have larger accessory carry affordances and are easier to pull bulky items into and out of. 

What sets the Exploration Pack apart? Besides the true vest-like design that hugs weight to the upper back, as described above, the next most notable difference is that the accessory affordances are rigorously minimalist. Take a look at the execution on subtle retention straps and you’ll see they are as subtle as possible, from the slender shock cord retention loops that snap over the top of soft flask nozzles to the chest straps made of the narrowest flat webbing available.  

Competitor packs sport various combinations of waist belts, drink tube retention straps, compression straps, handle loops, external stretch pockets, zipper pulls, etc. These features aren’t necessarily bad – The Nathan Crossover 15 pack, with intuitive organization and a hydration bladder, works really well for bikepacking, as I’ve described IN THIS REVIEW

The Black Diamond Distance 15 pack is a better choice for rock and alpine climbing, with a handle loop on top to hang from anchors, no-fuss access to the volume pocket, and a more user-friendly ice ax holder (two in fact). It can more credibly carry a coiled rope (but barely). It also holds a probe and shovel – I’ve used mine for backcountry skiing and multiple skimo races (an ultra-niche sport with its own comprehensive line of backpacks…). 

The Exploration pack inherently presents a variety of compromises. It’s cumbersome to pull out a large running shoe or puffy jacket through the small opening. The ice ax strap works, but is kinda tedious. You could lash a helmet on with some creativity, but it would take some rigging to keep it from flopping around. And it’s simply a poor option for backcountry skiing. 

Why would these compromises be worth it? Because the Exploration pack is ruthlessly optimized for running while carrying 5-10 lbs of gear. For folks who really want to enjoy the running itself on long distance, multi-day, and hybrid run/scramble activities, this high capacity running vest is the best option out there.

Drew Thayer