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Hydro Flask 21oz Standard Mouth Water Bottle
Hydro Flask21oz Standard Mouth Water Bottle

A Daily Driver.

With the Hydro Flask 21oz Standard Mouth Water Bottle, you're able to stay hydrated throughout the course of your work day. The 21oz easily fits in the side pocket of your backpack, shoulder bag, and your car cup holder, while the 18/8 stainless steel construction keeps your hot beverages hot up to 12 hours and your cold beverages cold up to 24 hours.

  • Stay hydrated throughout the day with this water bottle
  • Stainless steel construction is highly durable
  • BPA-Free and phthalate-free for your convenience
  • Keeps beverages hot up to 12 hours
  • Keeps beverages cold up to 24 hours
  • Reviews
  • Q & A


  • Familiarity: I've used it once or twice and have initial impressions

I have several different styles of Hydro Flask bottles. This is a perfect fit for your hand due to its slim design. Great for water (or whatever you prefer) on the go. Durable with bright colors.

Essential for anyone that drinks liquids

    This water bottle is great! It is slightly heavy and would not necessarily recommend this to someone who will be backpacking due to its weight but if they want their colds to stay cold, and their warms to stay warm then this will do it. I have owned several Hydroflasks in the past and have to say this is my favorite size. It fits really nicely in my Subaru Outback's cup holder but is tall enough to be able to store my daily fluids. I would say that I do not think the new lids are quite as good in terms of insulation as their last models.
    I have yet to test the insinuating properties in Utah's summer but have high hopes that my fluids will remain at a perfect temperature throughout my entire day.

    Great Bottle

    • Familiarity: I've put it through the wringer

    This is my 2nd hydro flask bottle. Slightly bigger than my previous one. No complaints.


    • Familiarity: I've put it through the wringer

    These are my go-to gifts this year. I pretend like I'm Oprah, because EVERYBODY gets a hydroflask! I got this one for my 10 year old niece who keeps her water bottle in her backpack which, naturally, gets banged around. The durability on these things is unmatched. Added bonus: I once had a lid that leaked and reached out to Hydroflask and they sent a replacement within a day!

    Great bottle

    • Familiarity: I've put it through the wringer

    I have several hydro flasks that are used. Like the others, this is great at keeping things warm or cold. The coated finish is pretty durable, but can be chipped, dented or scratched if you really treat it harsh.

    All The Insulation

    • Familiarity: I've put it through the wringer

    I have been hoarding insulated water bottles as of late. I love taking a sip of ice-cold water toward the end of a tough hike. These are pretty slender and fit into the external pockets of most bags with ease. They don't leak when closed and can take quite a beating. They will show battle damage over time, but I feel like that adds to the character.

    Keeps Ice on hot days

    • Familiarity: I've used it several times

    Great water bottle that comes in fun colors

    Great Gift size!

    • Familiarity: I've put it through the wringer

    I got 11 of these to give out at the family christmas party, upgraded white elephant gifts. The Blue is Sooo pretty. The worst thing is trying to decide a color. Keeps hot hot, cold cold. for better performance, cool or heat the inside with the tap before final filling. you can have ice all day and the next, but I just put my drinks in cold and it keep them good. even in the sun or over a heater. I love the loop, super handy that it fits in cup holders.

    I do enjoy the ease of access to clean on the larger wide mouths more. but I do how easy this fits into a pack or cup holder. 20oz with the additional loop lid is a great option, also go the straw lid.

    Great Flask

    • Familiarity: I gave it as a gift but have feedback to share

    Got this as a gift and the person has loved it so far. Keeps cold drinks cold and hot drinks hot.


      the classic hidroflask. i have all different sizes. i got thgis one for my kid and he loves it


      • Familiarity: I've put it through the wringer

      What is there to say about Hydro Flask that people don't already know?! It keeps beverages cold for hours, the look of the bottle is trendy and it's basically indestructible.

      I'll take this bottle on a hike and leave it in the car to come out to an ice cold drink with the ice still in there! You can literally never gone wrong with any of Hydro Flask products!

      So far, real good

      • Familiarity: I've put it through the wringer

      I've had the Hydro Flask 21oz water bottle for a month now and love it. It keeps drinks hot or cold for hours, closes tightly and has a convenient handle on the top. Highly recommended.

      Keeps Bevs Cold for days

      • Familiarity: I've put it through the wringer

      If not in direct sunlight, ice lasts in this bottle for over a day sometimes, and even when the ice melts, it stays cold for a long time afterwards. Easy to pack and very durable. It seals nicely as well.

      Drink Water Feel Good

      • Familiarity: I've put it through the wringer

      This water bottle is awesome. It always amazes me when I leave ice in the bottle and wake up the next morning to still find ice in my water! Couldn't ask for any more, hydro flask does not disappoint

      Needed the new colors

      • Familiarity: I've put it through the wringer

      These Hydro Flasks have a lifetime warranty. If your water is not cold/hot like it used to you can send them to Hydro Flask!! That is a huge perk. But, sometimes you just want the new color, so here I am buying the new color. The new lid is a huge upgrade. I don't feel like my finger will break off when I carry it around.

      Keeps my water cold!

      • Familiarity: I've used it several times

      This bottle keeps cold liquids cold. Also, my water doesn't have the plastic taste it gets from plastic bottles. Great colors also.

      Kid tested water approved

        I love my hydro flask its my favorite vessel for h20. It is also my 1-year-old son’s favorite tool for banging on the kitchen floor at 6am. As its metallic ring pierces through the sleeping household, I’m reminded how much I Love. My. Hydro Flask.

        Top Bottle

          Hydroflask knows whats up- they make a great bottle, and they actually WORK to keep your beverages hot or cold! Super easy to clean too, so you can put a variety of drinks in it and the bottle won't cling on to the taste. Very durable, easy to swap out the caps- what's not to love!

          Switched out my workout bottle

          • Familiarity: I've put it through the wringer

          Keeps water tasting good and cold for hours. I switched out my insulated plastic bottle I usually use when teaching spin classes for this one. Love Hydroflask.

          She loves it

            I bought this for my wife, she spent around 30 mins just picking between the rad colors.

            Added bonus: this thing keeps drinks cold or hot for hours!