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Sitting inside Nemo Mayfly Osmo 2P backpacking tent

Nemo Mayfly Osmo 2 Tent Review

Emily Wilson (gear tester)
Saray Tory bio photo
Eli Bernstein bio photo
Feb 14, 2025
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Our Take:
4/5
The Nemo Mayfly Osmo 2 ($400) is a solid choice for backpackers who want a durable yet lightweight tent that won’t break the bank. It’s heavy for a semi-freestanding tent at three-and-a-half pounds, but still undercuts most of the freestanding competition—and comes with perks like a thicker-than-average bathtub floor and a comparatively low price tag. Overall, the Mayfly strikes a nice balance for recreational backpackers who care about longevity, but there are weaknesses to its semi-freestanding design.
Interior Space

Interior Space

3/5
Weight & Packed Size

Weight & Packed Size

3/5
Weather Protection

Weather Protection

2.5/5
Durability

Durability

4/5
Ease of Use

Ease of Use

3.5/5
Sustainability

Sustainability

4.6/5

Type

Semi-freestanding

Packaged weight

3 lb. 8 oz.

Floor dimensions

85 x 52/43 in.

Capacity

2P (3P)

Pros

Color-coded and modernized components make the tent easy to set up.
Reasonably priced, especially considering its combination of weight and size.
Durable materials and Nemo’s sag-resistant Osmo fly.

Cons

Heavier than most tents with a similar-sized floor plan.
No interior pockets located along the tent’s base means you’re always reaching for your items.
Rainfly attachments come loose (or undone) in heavy winds.

With almost 28 square feet of space in a tapered floorplan (43 in. at the feet, 52 in. at the head), the Nemo Mayfly Osmo 2 tent can accommodate two regular-sized (20-in. wide) sleeping pads. The ridge pole and arching, pre-bent main pole significantly increase the tent’s height both at the head and throughout, allowing me to sit fully upright without my head hitting the ceiling. (I’m 5-foot 6 inches tall and could change a shirt without having to scrunch.) This design (along with the 42-inch peak height) makes the Mayfly feel larger on the interior than my Big Agnes Tiger Wall, which has a 39-inch peak height and doesn’t use a pre-bent pole.

I slept solo in the Mayfly while on a backpacking trip with friends in Washington State’s Enchantments. While the tent provided a generous amount of space for one, adding another person would have been tight. The tent’s tapered floorplan also makes it inconvenient to sleep head-to-toe with a tentmate. And if you or your tentmate has a penchant for rectangular, wide-sized sleeping pads (which measure 25 in. across), this isn’t the tent for you—they’ll fit at the head, but will have to overlap at the foot. Overall, the Mayfly is manageable for two people traveling with lightweight sleeping gear, but certainly not as spacious as a trekking pole shelter or untapered tents like the REI Co-op Trail Hut 2 (read our Trail Hut review) or Half Dome SL 2+.

Arranging two sleeping pads inside Nemo Mayfly Osmo 2P backpacking tent

Although Nemo classifies the Mayfly as a lightweight backpacking tent, it’s objectively hefty compared to other semi-freestanding designs. At 3 pounds 8 ounces, it weighs a pound (or more) heavier than Big Agnes’ Tiger Wall and Fly Creek and is even heavier than Big Agnes’ fully freestanding Copper Spur (3 lb.). That said, the extra ounces are put to good use in the form of increased durability and—when compared with the semi-freestanding models—slightly more interior space due to the extra headroom.

The Mayfly packs down to roughly 6.5 by 19.5 inches, which is larger than the Copper Spur (4.5 x 19.5 in.) and Tiger Wall (5 x 18 in.). Some will appreciate the way Nemo’s square-shaped stuff sack fits into their backpacking pack; those who routinely store their tent on the outside of their ultralight backpack might object. For my purposes, I was able to easily fit the Mayfly inside my 65-liter Osprey Ariel backpack along with my other sleeping gear, layers, and four days' worth of food. For solo backpacking trips, most people will want something slightly lighter, but if you’re sharing the weight (the Divvy Cube stuff sack is built so that the poles and tent can be split up), the Mayfly is a good option.

Nemo Mayfly Osmo 2P backpacking tent packed size

I tested the Mayfly in a range of trying weather conditions, notably on early-summer trips in Washington State’s Glacier Peak Wilderness and its smaller Enchantment range. In all types of moisture, the Mayfly fared well thanks to its Osmo rainfly and 68-denier PU ripstop floor (note: this floor is much thicker than that of most competitors—for reference, the Big Agnes Tiger Wall’s floor is 15D). Nemo’s proprietary Osmo fabric uses a poly-nylon blend that the company claims has longer-lasting waterproofing than similar materials and stretches minimally when wet (one-third that of other nylon flys). In practice, I had nothing to complain about: While camping on snow, the bathtub floor valiantly kept moisture out, even without a ground cloth; when the skies unleashed high in the Enchantments’ “core zone,” the rainfly prevented any rain or moisture from entering the tent and was still taut in the morning.

However, the strong winds my group encountered while camping in the Enchantments revealed a significant weak point in the Mayfly’s performance. The rainfly attaches to the tent by inserting a pin into a slot at each corner and then twisting until the pin is perpendicular to the slot. Without wind, this system works well; but during the heavy winds I experienced, the pins came out of their slots several times throughout the night, which resulted in a detached (and very loud and flapping) rainfly. I also noticed that the rainfly’s cord locks loosened in the wind, likely contributing to the pin-and-slot attachments coming undone. I wouldn’t wish this kind of sleepless night on anyone, and would only recommend the Mayfly for lower-elevation and sheltered campsites.

Securing Nemo Mayfly Osmo 2P backpacking tent rainfly in wind
Nemo Mayfly Osmo 2P backpacking tent pole grommet

The Mayfly features a 68-denier PU ripstop floor, which is much more substantial than most ultralight tent floors (the average is around 15 to 20D). The floor felt remarkably sturdy without a ground cloth (Nemo does offer a 70D footprint for $70) and I did not experience any abrasions or snagging when camped on granite and at forest campsites with pokey sticks and rocks. Similarly, the no-see-um mesh fabric on the tent body felt durable without being too heavy, and you get an average amount of nylon on the tent body (more than a mesh-heavy tent like the Big Agnes Fly Creek), which is arguably more long-lasting than mesh. Nemo does not provide a denier for the Osmo rainfly fabric as it’s made with two different fibers, but it felt significantly more robust than my Tiger Wall’s 15-denier rainfly (for more, read the Tiger Wall UL2 review).

Although the Mayfly did not perform well in high winds, the lightweight aluminum poles exceeded my expectations. I’ve had carbon poles snap on me, so it was a relief to see that the aluminum poles barely bent in the strong gusts (I was happy to have the included repair splint just in case). Overall, the Mayfly is sturdier than most semi-freestanding tents, which is one of the key benefits of its heavier-than-average design.

Securing poles on Nemo Mayfly Osmo 2P backpacking tent

I found the setup process for the Mayfly Osmo 2 intuitive and easy to do on my own. The tent pitches with one main Y-shaped pole and a ridge pole, and mercifully has color-coded webbing and pole ends to serve as guides. The ends of the poles have metal balls (dubbed “Axial corner anchors”) that snap into place at the tent’s corners—a surprisingly satisfying experience. However, I noticed that snow or small pebbles tended to get into these sockets, which I then had to clean out to get the tent pole to snap in securely. The rainfly is anchored to the tent using the combination of a pin and slot, which I detailed in the Weather Protection section above. My initial take on this hardware was that it was cool, innovative, and fun to use—but after a windy night that forced me out of my tent multiple times to reattach the fly, it lost its appeal.

Because the Mayfly is semi-freestanding, you have to stake out the two corners at the foot for the tent to be fully set up. Several guylines can also staked out to create more stability in heavy winds. This does require good anchors, which were hard for me to find while camping on granite slabs and in the snow. I had to make deadmans (buried anchors in the snow) and scavenge for small boulders, making the setup process long and onerous. This is one of the primary downsides of a semi-freestanding backpacking tent; as a result, I’d recommend the Mayfly for those who stick to campsites with good ground anchors (read: dirt), but it’s not a great pairing for hikers who frequent above-treeline areas where they’ll be camping on rock and snow.

Staking out Nemo Mayfly Osmo 2P backpacking tent
Setting up poles of Nemo Mayfly Osmo 2P backpacking tent
Nemo Mayfly Osmo 2P backpacking tent pole structure

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Longevity

Choosing durable outdoor gear is perhaps the most effective way to reduce environmental impact—the longer it lasts, the less it needs to be produced. Our proprietary longevity rating evaluates overall build quality based on factors such as materials, fabric denier, component durability (including zippers and toggles), real-world performance as reported by our field testers, and our experiences with the brand.

With its double-wall design, the mesh body of the Nemo Mayfly Osmo allows for great ventilation and moisture control. Nemo also included a strut vent above each vestibule door to prop open to increase airflow. On a clear night, the rainfly can be tied back on each vestibule door. Unlike some other tents I’ve used, Nemo designed the Mayfly with non-mesh fabric on the door, which allows for slightly more privacy but does have a slight negative impact on ventilation. I’ve noticed no ventilation issues while sleeping solo in the tent; while sharing it with my climbing partner at the Glacier Peak basecamp, propping open the vents seemed to do the trick.

Interior Storage
The Mayfly includes one very generously sized pocket overhead that can hold large items—I used it to store my base layer, kindle, and a couple of other small items. There is also a smaller rectangular pocket on the wall behind that head, where I kept my phone and charger a bit closer in reach. The Mayfly also features a pair of Nemo’s unique nightlight pockets, made with orange material to dampen the light of a headlamp and create a nice ambient glow. Though I appreciated the large pockets, I wish the Mayfly had pockets closer to the bathtub floor for easier access without having to sit up.

Nemo Mayfly Osmo 2P backpacking tent rooftop storage
Headlamp inside Nightlight pocket of Nemo Mayfly Osmo 2P backpacking tent


Vestibules
The Mayfly’s two vestibules (7.1 sq. ft. each) accommodated my 65-liter backpack and hiking shoes. While my backpack was completely covered by the rainfly, it was a close fit—one rainy night, mud splashed under the fly and onto my pack. For comparison’s sake, these vestibules are slightly smaller than those of many competitors (including the Big Agnes Tiger Wall), which are generally about 8 square feet.

Backpack inside Nemo Mayfly Osmo 2P backpacking tent vestibule

Nemo Dagger Osmo 2 ($500): Maximize Your Backcountry Comfort
The Nemo Dagger Osmo is a step up in comfort from the Mayfly with the price tag to prove it. Unlike the Mayfly, the Dagger is a freestanding tent (the corners of the foot end are pole-supported vs. the single pole running down the spine of the Mayfly), which translates to more versatility in choosing a campsite and an overall more stable and roomy build. It also prioritizes comfort with a rectangular floorplan—significantly wider than the Mayfly at the foot—more headroom throughout, and roomy vestibules (11.4 sq. ft. each compared to the Mayfly’s 7.1 sq. ft.). Surprisingly, the Dagger is only 7 ounces heavier than the Mayfly thanks to a thinner fabric set. We think the Mayfly offers a better balance of durability and weight, but the Dagger is a great option for comfort-seeking backpackers who still want to travel relatively light. For a deeper dive, see our Nemo Dagger Osmo 2P review.


Big Agnes Copper Spur UL2 ($550): Better Space-to-Weight Ratio
Big Agnes’ Copper Spur is one of the most well-rounded backpacking tents ever made and thus is a great gold standard against which to compare the Mayfly. For 3 pounds (a half-pound lighter than the Mayfly), the Copper Spur features a freestanding design, which is more stable in high winds and won’t require you to hem and haw over your campsite—just set the tent up on rock, snow, or dirt, and it’ll stand on its own. The weight savings and freestanding design are enough to warrant the $150 price bump, which will be worth it for backpackers wanting the top-shelf combination of space-to-weight. However, the Copper Spur’s thinner fabrics (15D and 20D) will require extra care. For more, read our review of the Big Agnes Copper Spur UL2.

Nemo Mayfly Osmo 2 ($450)
Sitting inside Nemo Mayfly Osmo 2P backpacking tent
4/5

While the Mayfly ranks a tad below Nemo and other brands’ premium ultralight offerings, this tent still has much to offer. It’s durable, competitively priced, exceptionally waterproof, and light enough for most backpacking trips. However, it performs poorly in wind and doesn’t offer a good space-to-weight ratio.

Type
Semi-freestanding
Packaged weight
3 lb. 8 oz.
Floor dimensions
85 x 52/43 in.
Capacity
2P (3P)
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Interior Space

3/5
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Weight & Packed Size

3/5
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Weather Protection

2.5/5
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Durability

4/5
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Ease of Use

3.5/5
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Sustainability

4.6/5
Nemo Dagger Osmo 2P ($550)
Nemo Dagger Osmo 2P backpacking tent vestibule
4.7/5

The Nemo Dagger is made for hikers who want to max out backcountry comfort. The tent doesn’t levy too harsh of a weight tax, considering the room it provides, and it’s a well-constructed model. Its high price tag would fit better on a lighter design, though.

Type
Freestanding
Packaged weight
3 lb. 15 oz.
Floor dimensions
88 x 50 in.
Capacity
2P (3P)
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Interior Space

5/5
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Weight & Packed Size

3/5
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Weather Protection

4/5
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Durability

3.5/5
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Ease of Use

5/5
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Sustainability

5/5
Big Agnes Copper Spur UL2 ($550)
Big Agnes Copper Spur UL2 backpacking tent at campsite
4.8/5

Our favorite do-it-all backpacking tent, the Copper Spur, gets a welcome update for 2025. It’s now even lighter, with updated fabrics and the same accommodating dimensions. Yes, its price is hard to swallow, but this tent won’t let you down.

Type
Freestanding
Packaged weight
3 lb.
Floor dimensions
88 x 52/42 in.
Capacity
2P (1, 2XL, 3, 3XL, 4, 5P)
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Interior Space

4/5
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Weight & Packed Size

4/5
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Weather Protection

4/5
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Durability

2.5/5
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Ease of Use

4/5
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Sustainability

3/5

Is the Mayfly for You?

The Nemo Mayfly is a bit of a curious tent in terms of where it sits within the greater market. Its main calling card is that it’s more durable than most backpacking tents of similar weight, with a 68-denier floor (most 3-lb. tents run around 15D to 20D) and an Osmo fly that’s reliably waterproof and does not sag when wet like other forms of nylon. As a result, it makes an intriguing option for practical backpackers looking for a great combination of price, durability, and weight savings, as long as you know what you’re getting with the semi-freestanding design (it isn’t ideal in serious wind or on rocky terrain). There are certainly lighter tents with similar amounts of interior space, but for its price and longevity, the Mayfly has carved out a small niche for itself within a competitive market.

Nemo Mayfly Osmo 2P backpacking tent set up in mountains

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