Osprey Dyna LT Review

An in-depth review of the Osprey Dyna LT.

By on November 23, 2022 | Comments

Last summer, I was interested in acquiring a minimalist hydration vest while prepping for fall trail races. Finding a well-fitted vest with just the right capacity to accommodate the essentials, without being overkill for racing, is undoubtedly a common desire in the ultrarunning and trail running community.

This summer, I found myself prepping for a fall baby. The training calendar has been pretty different, but my desire for a well-ventilated vest with minimal extra fabric, and convenient hydration and snack pockets, quite similar. Osprey’s all-new minimalist Osprey Dyna LT ($85) hydration pack and its women’s-specific fit have kept me cool, hydrated, and fueled through the demands of my second and third trimesters of pregnancy and I look forward to using it post-pregnancy as well.

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Osprey Dyna LT front view

The Osprey Dyna LT hydration pack. All photos: iRunFar/Annie Behrend

Osprey Dyna LT Sizing and Fit

Osprey has been redesigning their line to improve fit, with an extra focus on women’s-specific fit. With this in mind, the Osprey Dyna LT comes in three sizing options, rather than two as per previous models. To determine the correct size, Osprey’s website provides a tutorial to show you how to collect an accurate measurement of your torso length.

In my case, essentially every other upper body dimension has significantly changed while pregnant except my torso length, leaving me skeptical that this measurement alone could result in a well-fitted vest. Aside from the fact that the soft flasks ride a bit high — which is undoubtedly influenced in part by my launch into a DD-size chest — the vest remains comfortable in my normal size medium. While I anticipate this vest to fit even better upon my return to baseline — a B-size chest — I have yet to experience any chafing around the neck or elsewhere due to too snug a fit and/or abrasive fabric.

Osprey Dyna LT Hydration Options

The Osprey Dyna LT comes with two Hydraulics 360-milliliter (12 ounces) soft flasks. Bungee loops secure the top of the soft flasks in place so they don’t slouch down into the pockets. I have zero leaks to report from my use of these soft flasks, which are interchangeable with the Hydraulics 360-milliliter soft flask that comes with the Osprey Duro/Dyna Handheld. One could potentially slide an extra soft flask through the back kangaroo pocket of the vest, if desired; however, the Osprey Dyna LT really is not otherwise designed to house hydration beyond 24 ounces via the front soft flasks.

Consistent with the only other women’s-specific vest I’ve used, the front soft flasks seem to ride relatively high. In the case of the Osprey Dyna LT, however, I anticipate this to improve somewhat during my postpartum voyage back to a more universally medium-sized upper body.

Osprey Dyna LT detailed front view

A detailed front view of the Osprey Dyna LT.

Osprey Dyna LT Storage Options

The storage capacity of the Osprey Dyna LT is not huge, but it has a space for all the essentials you need to take with you on a daily run. Historically, I’ve been notorious for erring higher versus lower when given a range of vest-capacity options, in part because 50-mile-plus racing opportunities were my go-to. I have amusing memories of Black Canyon 100k, with a good pal who managed to misplace her hamburger.

After searching every nook and cranny of what was likely a 12-liter pack, she found the elusive burger the next day stuffed into a pocket of her shorts. While higher capacity packs certainly have their place, I have really enjoyed the simplicity of having just enough room in this hydration vest for my phone, key, credit card, water, and snacks. Each of those items has a logical home and not five places they could be.

Osprey Dyna LT pockets close up

The Osprey Dyna LT’s front pockets.

An extra-large stretch mesh soft flask pocket is available on both the right and the left; these pockets can also house food or hold your phone if you’re not using both soft flasks.

At the base of these extra-large pockets are two lower stretch mesh pockets, for food and other essentials. Like the extra-large flask pockets, these smaller pockets are accessible from the top. A bright red clip is housed in the small right-side pocket, no doubt as a way of ensuring that a key doesn’t jump ship if placed there.

A vertical zippered harness slash pocket is accessible from the medial left side of the vest; contents slide just in front of the extra-large pocket and just behind the lower/smaller pocket. A bright red safety whistle is housed in the slash pocket. I wish every piece of running attire had at least one zippered pocket for valuables; this is my go-to place to confidently stash car keys and credit cards.

The final storage space is a large, dual-entry stretch mesh rear pocket. I routinely toss my phone in this rear pocket, which lays flush enough against my back that I have yet to experience anything voluntarily popping out. With access available from the top, reasonable shoulder mobility is required for the seamless retrieval of items from the back.

A simple mesh racerback design extends from the rear pocket up and over the shoulders. I love this design for a minimalist pack, as it makes it very easy to keep cool. The vest is secured at the chest with dual snap-in adjustable/removable straps, which are easy to use. Most packs I’ve used seem to have abundantly long chest straps. While a seemingly small detail, I’ve appreciated that strap tails on the Osprey Dyna LT can be easily secured so as to not flap around.

Osprey Dyna LT detailed back view

A detailed back view of the Osprey Dyna LT.

Osprey Dyna LT Overall Impressions

The Osprey Dyna LT has been an integral part of my everyday running and hiking wardrobe as the increased calorie and hydration demands of pregnancy have returned. The vest is svelte and doesn’t feel like overkill on shorter runs. Despite several references to stretch mesh, the structure of the Osprey Dyna LT itself doesn’t feel especially stretchy when compared to the amount of stretch in Salomon’s line of vests.

The honeycomb fabric that lies underneath the front pockets and extends over the shoulders and down to the rear pocket is limited in its elasticity, but remains comfortable. I wonder if the nature of the material in places I’ve previously worn holes through softer mesh will prolong the life of the vest and protect from the wear and tear that comes with routine use. Time will tell!

Despite cooler temperatures around the corner, I anticipate the Osprey Dyna LT will continue to hang out at the top of the gear pile as my hydration requirements only increase once again when this tiny baby joins me earthside.

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Other Versions of the Osprey Dyna LT

The brand also makes a men’s specific version of this hydration pack, the Osprey Duro LT, which has the same feature set.

Call for Comments

  • Are you running in the Osprey Dyna LT? If so, what do you think about it overall?
  • If you are using the men’s version of this pack, the Osprey Duro LT, let us know what you think about it, too!

[Editor’s Note: If you’re affiliated (i.e., an employee, ambassador, etc.) with a brand, please share your relation in each of your comments on this article. Thanks!]

Osprey Dyna LT side view

A side view of the Osprey Dyna LT.

Annie Behrend

Annie Behrend is a gear reviewer for iRunFar. She’s been writing about running gear since 2020. Aside from iRunFar, she’s authored and co-authored nutrition and fueling-related publications in research journals. As a registered dietitian and ultrarunner, she’s worked one-on-one with athletes, primarily runners, since 2013 to optimize performance via fueling and hydration. Based in temperate southern Oregon, Annie has year-round access to marvelous trail systems and public lands that she shares with more wildlife than she does people … the perfect paradise.