Ok, let me start with the obvious. No, you cannot go swimming in Grand Prismatic Spring or any other geyser in Yellowstone National Park. While it is indeed illegal, the truth of the matter is that most of the natural geothermal features of Yellowstone are just a few degrees shy of boiling water, subjecting the would-be bather not just to federal law, but the law of physics, and near certain death :)

That said, I distinctly remember that in Yellowstone, there are some places in the rivers that you can actually swim and experience a hot springs like effect. Where the runoff from the geothermal features meets the river (like Firehole), the mixture can be quite pleasant.

I am bringing my kids to Yellowstone in August, and I want to take them there. Unfortunately, within my books, I can't seem to remember where one can do this.

To the best of my recollection, on the way up from Norris to Mammoth Hot Springs, there is a place where you can pull off on the side of the road and get in the river, where the runoff from a hot spring naturally warms the river. Does anyone know the name that I could google to do more research?

2 Answers 2


Found it!

It's called the "Boiling River", and information is here: http://www.yellowstonepark.com/swim-yellowstones-boiling-river/

Additionally, there is some swimming allowed in parts of the Firehole River, along the scenic drive.

Update, just got back from Yellowstone, and candidly, the Boiling River is possibly the most underrated attraction in Yellowstone. The Boiling River itself is actually the Gardiner River, along a trail called "Boiling River." The trailhead is in a parking lot just as one crosses the WY/MT border, about a mile north of Mammoth Hot Springs. From the parking lot, expect a walk of about 3/4 of mile, whereupon, in the middle of summer at least, you will find a bunch of people swimming.

The Boiling River area gets its warmth from an outlet of Mammoth Hot Springs. There is a little pool enclosed by rocks that is a bit hotter than a hot tub. (Based on my experience, I'd guess the water to be about 104 to 106 degrees F - just slightly hotter than I like in the hot tub.) The water spills beyond a semi-circle of rocks, however, mixing with the otherwise colder water of the Gardiner River. The result is a very definite pattern of warm and cold in the River that is just amazing.

Two things to keep in mind:

  1. This is a national park, and so conservation is high on their minds. No soaps, no horseplay, basic "behave" kind of stuff. (No nudity, for example, is on the signs, but that isn't really a conservation measure.) There is a sign at the front that warns visitors that this is one of those places that is getting "loved to death."

  2. The current is incredibly strong. My nearly 11 year-old daughter was nearly swept away at one point. Grant you, there are enough people to catch you, but the rocks make it hard to stand, and the current is just incredibly pervasive. All in all, it actually makes for a very enjoyable experience.

Highly, highly recommended.

  • For a slightly (Summer 2015) more recent note - while the current is pretty strong, the swimming area is bordered by rocks - you're unlikley to get swept away, although you do need to be firm on your feet. When I visited, the water coming from the Boiling River itself was dangerously hot - would probably scald you pretty fast. In the area of mixing, it was pleasant enough, but the mixing could be odd - it was entirely possible to have one foot uncomfortably hot while the other was going numb.
    – CMaster
    Mar 21, 2016 at 11:52

I recall nude swimming at Boiling River late in the evening years ago when I visited the park as part of a 3300 mile bike trip around the northwest. I was in my teens and we spent a couple of nights camping in the area and visited the hot springs, where, after dark, a few folks dared to bare, mostly a college-aged crowd but a few young teens like myself (I didn't dare to bare it all though :)

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