Do Hydro Flask Lids Fit on Nalgene Bottles?

I've always kept at least one Nalgene Bottle in my rotation for about as long as I can remember. They’re lightweight, durable, and cheap enough that I don’t mind replacing them when I inevitably lose one. 

My only real complaint is that the twist-off cap is a little too basic, especially because I prefer wide mouth bottles that are a bit harder to drink straight out of. I've also got a really great Hydro Flask UV lid that kills bacteria and allows me to drink water straight from the river. I would love if I could combine the light weight Nalgene bottle with the Hydro Flask lid.

It led me to wonder if I could use the lid from any of my other bottles on my Nalgenes instead. My Hydro Flask lids are some of my favorites, but how do they actually fit on Nalgene Bottles? 

Some older Hydro Flask lids fit perfectly on wide mouth Nalgene Bottles but, unfortunately, their newer lids don’t seem to. Hydro Flask redesigned their bottles in early 2020 and, along with several other changes, changed the width of the threads on their lids — enough that they no longer fit snugly on Nalgene Bottles.

Narrow mouth Hydro Flask lids are NOT compatible with narrow mouth Nalgene bottles as the lid threads are on the opposite sides and thus they cannot connect.

Nalgene lids seem to fit onto Hydro Flask bottles, however because they lack a rubber gasket the lid will leak when placed on a Hydro Flask bottle. I have tested multiple different Hydro Flask lids on multiple different Nalgene bottles and visa versa and the fit is just not quite right.

The bottles seem to be JUST different enough that the lids aren't compatible.

If you want a new lid for your Nalgene that’s more than just a simple, twist-off cap, check out my list of the 12 best Nalgene lids.

Do Hydro Flask Lids Fit On Nalgenes?

Hydro Flask and Nalgene are my 2 most used bottles. I am regularly interchanging them both for climbing, bushwalking or just using at my desk.

They are often hanging out in the drying rack together and I do love the flip out straw lid for my Hydro Flask. It just makes sipping on water throughout the day much easier and it increases how many bottles of water I drink per day.

I was so stoked on the lid, I wanted to take it to the climbing gym on one of my Nalgenes or even just use it at home.

The only problem was, it didn’t fit. 

It sort of screwed on but was slightly crooked and leaked everywhere. I tried it on another couple of my Nalgenes with no luck either. 

Looking at the threads of each of the lids and the bottles you can see that they are only a tiny bit different. The most noticeable difference is the Nalgene thread wraps around more on the bottle when compared to the Hydro Flask thread which hardly overlaps itself at all.

It seems this slight difference does cause the lids not to be compatible.

I searched around and stumbled across people who had also used Hydro Flask lids on thier Nalgenes — like this Redditor who used their Hydro Flask flip top on their 32 oz Nalgene or this Redditor who shared lids between many of their wide mouth bottles

But these posts are both from over 3-4 years ago, before Hydro Flask changed their design so maybe that's why it seemed to work for them and not me.

I tried to rescrew a bunch of times and tried a variety of different Hydro Flask lids but I was out of luck. None seemed to work property.

Narrow mouth Hydro Flask lids DO NOT work on narrow mouth Nalgene bottles at all. The threads are on the wrong sides so it's not even worth trying.

Do Nalgene Lids Fit On Hydro Flask Bottles?

Nalgene lids screw onto Hydro Flask bottles really easily and on the surface it feels like a perfect match.

However, if you over tighten the Nalgene lid can pop out and a bit and also (and most importantly) when you shake the bottle with a Nalgene lid on it some water leaks out.

It's not a huge amount so if you were in a tight spot you could use a Nalgene lid on your Hydro Flask and just try to keep it upright. But it's definitely not watertight and if you have the right lid for your Hydro Flask you're much better off using that.

New Hydro Flask Lids Don’t Fit (Most) Nalgenes

Come to find out, in early 2020 Hydro Flask redesigned their bottles and (apparently) slightly changed the width of the threads on their lids. 

If you have an old Hydro Flask lid laying around, it’s very likely to fit on your wide mouth Nalgene Bottle — though I can’t say it’ll work 100% of the time since I no longer have any old Hydro Flask lids to test. 

To see if your Hydro Flask is an original or updated model, check for a lip around the neck of your bottle. If it has a lip, it’s an original, and if it doesn’t, it’s a newer one.

None of my new Hydro Flask lids fit on any of my Tritan Nalgenes but, just to add some confusion, fit perfectly on one of my Ultralite Nalgenes and not so great on the other.

I have no idea why. 

Ultimately, it’s safe to assume that most Hydro Flask lids won’t fit on Nalgene Bottles. And as more time passes and more old Hydro Flask lids are lost, broken, and replaced, it’ll only become more true.