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Protection for ultralight trips and an insurance policy for unplanned nights out.

When the wind and rain start to blow during your solo mission, reach into your pack, and pull out the super-compact and lightweight Black Diamond Twilight Bivy. The water-resistant NanoShield fabric seals out the elements as it surrounds your sleeping bag and breathes better than virtually any water-phobic fabric on the market. A zippered opening at the shoulders provides easy access and lets you sit up to stretch your aching muscles in the middle of the night.

  • Single-wall bivy design saves weight by eliminating the need for a tent canopy, poles, and fly; ideal for year-round minimalist applications
  • Breathable, abrasion-resistant, and highly packable NanoShield fabric features a silicone NanoCell coating to protect against rain, snow, and wind
  • No poles to save weight for minimalist excursions
  • Mesh panel over face keeps out bugs, helps cut down on condensation buildup, and is removable
  • Small size fits easily into a backpack, bike pack, or haul bag
  • Optional footprint sold separately

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Here's what others have to say...

is this Bivy waterproof?


At most this is water-resistant. It has the Nano-Shield treatment which is a silicone treatment.

Shoot me an email anytime you have questions!

Jared D.

Expert Gearhead


It works great in snow. I've never had it in a hard rain. being in any bivy in the rain is a miserable experience. Bring a tarp!

Unanswered Question

Is the mosquito net fine enough so that it works with midges too (the ones in Scotland)? I am looking for a light and small bivy for a bikepacking tour around Scotland.

Unanswered Question

Hi, I am wondering how I can roll up and...

Hi, I am wondering how I can roll up and fix the mosquito net in the BD Twilight Bivy when the bivy is closed.

Closing the net when the bivy is open is easy.

Rolling down and fixing the net with openbivy cab be done by using the loop and the little cord with the tanka.

Now, this loop/cord method does not work with closed bivy.

Do I always have to close net and bivy or can I roll up the net also when the bivy is closed? Thanks a lot for your answers.


I'm 6'2", 175 pounds. Is this bivy will...

I'm 6'2", 175 pounds. Is this bivy will fit me or I have to find another model? (any tought on other fully enclosed bivy that packs small as the twilight?)

Best Answer

The bivy is 6'10" long. With a long-sized bag, you should just fit inside.

im wondering if you have to seam seal this...

im wondering if you have to seam seal this with mcnetts seam grip like all the other silnylon offerings from BD?

It's a decent idea. You don't really have seams that are exposed to the direct force of rain like you would on a tent, but it can still seep in.

I bought the BD Spotlight bivy, nearly the same as this one, and I did have to seam seal it myself

if i understand correctly, this bivy has...

if i understand correctly, this bivy has one zipper running across the shoulders and thats it? What about venting down by the feet, easy entry, etc...

That's it. The fabric is very breathable, so no venting. The zipper is wide enough that you should be able to side in easily, unless you're wide.


Worst Night Out In A Long Time...

    After reading some mixed reviews on this bivy, I decided to give it a shot in an effort to lighten up my kit by about a pound. I was hoping to use it in moderate weather in the alpine where little to no precipitation would be seen. As the weather forecast was looking beautiful, I took it out this weekend for a test run atop a snowy ridge in the Cascades. Ideal conditions, clear skys, light wind, no snow, and this thing managed to sucked hard. I woke up three hours into the night to find the inside of the bivy completely soaked. A few hours later and my bag was soaked through and no longer providing me warmth. I have no idea how the product description can claim bit of breathability, as this bivy was about as breathable as a trash bag. Quite a long and cold night from that point on. A point to note; I slept with the hood open and my face out into the air all night long. My breath did not contribute to the condensation in the bag. The seams were also sealed with Seamgrip prior to spending a night in it.
    It was a bummer that this bivy didn't work out as I would have liked. I don't recommend this, or any Black Diamond bivy made of this material to anyone who would use it in an alpine environment. I'm glad I tested it on a mellow climb where the only repercussions were a shiver bivy and a lack of sleep. Anything bigger and things could have been worse.
    Do yourself a favor and steer clear of BD bivys.

    What have I learned from this review? Do not seal the seams of this bivvy. I sleep great in it in my 0 degree down bag.

    I'm new to this bivy idea... I've got a...

    I'm new to this bivy idea... I've got a WM Ultralite with 38" in the foot. Would that somehow fit inside this bivy? or should I look for one with more foot-room?

    How durable is this super light fabric? ...

    How durable is this super light fabric? I plan on using it quite often and don't want to buy a new one every couple years. How long will this bivy last?

    It is pretty fragile but the question of how long it will last is really subjective. If you are bivying on flat ground with no rocks or sharp pointy objects like sticks or on a portaledge it will last much longer than on icy ledges and granite cliffs.

    my main concern with a bivy is not in...

    my main concern with a bivy is not in keeping me dry in a 10 hour downpour. Rather it is to protect my down bag from splashes coming off a tarp/open floor shelter/ snowcave/ dew, etc.

    Problem is that I am a warm sleeper and my down bag is notorious for not breathing very well by itself. Therefore, i need to make sure the bivy sack I buy can breath really well. Does anyone know how this BD fabric compares to eVEnt or membrain? I am desperately trying to avoid the dreaded bivy condensation

    The BD fabric is highly breathable and you should not encounter any problems. If you have issues you can always return for a full refund

    The NanoShield fabric is significantly more breathable than eVent or Membrain.

    Is a footprint recommened?

    Is a footprint recommened?

    Nope, you're fine. Silnylon bottom fabric is completely waterproof.

    Whats the ventailation like? The inside...

    Whats the ventailation like? The inside tag said theres a suffication danger.

    It's made out of a crazy breathable silicon impregnated nylon. Basically they coat each individual fibre with silicon which gives a high water resistance while still allowing airflow. It's not as breathable as no fabric, but it's about as good as it's going to get as far as single wall bivvy fabrics go.


    Great Ultralight Bivy

      I use this bivy for backpacking and car camping. It is extremely compact if compressed a little it's a little bigger than a baseball, light, and breathable. It's not entirely waterproof but will keep you dry from light rain and morning dew, it does a good job keeping the wind off as well. I usually pair it with a light weight tarp in heavier rain and snow. It's pretty spacious, I'm 5'8, 165lbs and I have tons of space to move around and enough room for my boots and clothes if needed. There are loops that you can easily tie up the cloth around the face area to keep it elevated but the material is so light I barely notice it when I sleep. Over this is an awesome bivy.

      Great Ultralight Bivy

      is it possible to lift the fabric up with...

      is it possible to lift the fabric up with so that it doesn't hang in you face? is there a loop that is already there or would you need to sew one on or use something else

      looking for a Bivy sack. I'm 6'4", size...

      looking for a Bivy sack. I'm 6'4", size 15 boot, need light weight for back packing- all season-, waterproof, durable- does any one have suggestions on bivy's they have used??

      This one is just too small for somebody your size. The Marmot Alpinist is similar, but with a little more room. I've tried the Integral Designs eVent bivy and its nice and long and breathes well, but weighs almost double what these weigh.

      does the fabric above your face fall on...

      does the fabric above your face fall on your face since there is no poles

      Is this left or right zip? If anyone has...

      Is this left or right zip? If anyone has anything to say about the use of this bivy in snow / inclement weather and the waterproof / breathability that would be great.

      It's neither right nor left -- just a zipper across the width of the bivy, up where your face is. You climb in from the top. It has a bug panel but can also be zipped entirely closed if conditions require.


      Great lightweight bivy!

        I bought this bivy for lightweight alpine use and for use in emergencies. In all my research this bivy had the best balance of weight, breathability, and weather resistance.

        I have used this bivy climbing Longs Peak and car camping. I have not encountered any real weather with this bivy so I can't testify to its waterproofness, but I can tell you that it breaths very well.

        Great lightweight bivy!