GRASSY FLATS · HARMONY POINT
Where can you do a Sauna and Cold Plunge in the Florida Keys?
Harmony Point at Grassy Flats in Marathon has a 12-person wood-fired sauna and three cold plunge tubs that fit 4 people each, open by the hour to hotel guests and visitors.
That’s rare down here. The Keys are built around getting on the water, not recovering from it, and most hotels between Key Largo and Key West don’t have a sauna at all.
12 PEOPLE
Wood-fired sauna capacity
3 TUBS
Four people per tub
1 HOUR
Bookable session
40–55°F
Cold plunge range
THE PLACE
What is Harmony Point?
Harmony Point is the wellness area on the westernmost point of the property: sauna, cold plunges, and an outdoor fitness area, facing the sunset.
The name comes from John Denny, a former Maui big wave surfer who has run meditations out on that point for years. It’s the recovery half of the waterman lifestyle. You came down and got worked by the wind. This is what you do on day three to get the most out of day four.
THE CIRCUIT
How Do I Use the Sauna?
01 / HEAT
12 - 15 minutes in the sauna
Dry heat, 170-190. Your heart rate climbs the whole time, and most people are up and around 150 to 160 by the thirteenth minute.
03 / COLD
3 minutes in the cold plunge
Go Straight in from the heat. Your heart rate drops fast, sometimes down into the High 50s or 60s. Three minutes is the target for the full benefit.
02 / WATER + RINSE
Before the plunge
Drink Water
Rinse Off (Required)
04 / RECOVER
3 minutes out
Don’t towel off and bolt for the sauna. Sit with it and breathe. Your body is working to warm itself back up, and that’s where a lot of the actual work happens.
Then back into the sauna and around again. If three rounds is too much, do two. Nobody is counting.
CHOOSE YOUR TEMPERATURE
How Cold is the Cold Plunge?
The cold plunge ranges from 55 degrees down to 40. There’s no prize for going straight to 40, and the three minutes matter more than the temperature.
The cold plunge temperature Range:
~55°F
First plunge of your life. Cold, manageable, you'll still be able to breathe normally after about a minute.
~50°F
The middle ground. Most people end up here by their second visit.
40 to 45°F
If you already do this at home, this is the one you came for.
RECOVERY
What Are the Benefits of Sauna and Cold Plunge?
The heat-to-cold swing is what you're after. That vascular constriction and dilation is the mechanism behind the recovery and the inflammation relief.
An average person burns somewhere north of 600 calories across 3 rounds, which is a strange number for an hour spent mostly sitting still. Your muscles are cycling the blood through the whole time, which is why this works on relieving the soreness from whatever you put your body through that week.
If three rounds is too much, do two. Nobody is counting. The first time through a 40-degree tub is the hardest part. After that you know what it is.
WOOD-FIRED HEAT
How hot is the sauna?
The sauna runs 170 to 190. It's the range you want if you're after the cardiovascular benefit, which is the whole reason the circuit works.
If that sounds like a lot, it is, and it's supposed to be. A steam sauna sits lower, somewhere around 120 to 140, and it feels hotter because of the humidity without doing the same thing to your heart rate. We can bring the temperature down if a group wants it cooler. It's a wood fire, so we tamp it down and let the room breathe for a few minutes. Just ask.
THE WATER
Is the cold plunge actually clean?
Yes. The plunges are cleaned daily. The tubs come from Emerge, and the filtration was built by John Kleener of Live Water Sports: a multi-stage system running on hydrogen peroxide instead of chlorine or bromine. It exceeds Florida Department of Health standards for this kind of water.
No chemical smell. Nothing that leaves your skin feeling stripped. Water that’s actually being turned over, not topped off.
The other half is on you. Shower between the sauna and the plunge, every round. The outdoor showers are right there. Don’t be that guy.
GUESTS AND VISITORS
Can you use the sauna and cold plunge if you are not staying at the hotel?
Yes. If you are a hotel guest, Harmony Point is included in your resort fee. Sauna, cold plunges, outdoor fitness area are all part of your stay. We ask you to book your hour at the front desk as availability is limited.
If you are not staying here, there are two ways in.
$35 per person
Harmony Point Hour
One hour of sauna, cold plunge, and outdoor fitness area access for $35 per person.
$75–$100 per person
Day Pass
Buy a Day Pass to the resort: With a day pass you get day use of resort which includes an hour at Harmony Point plus access to the kayaks and paddle boards for $75-$100 per person.
The day pass is the better deal for most people who've driven to get here. You're already in Marathon, you've already parked, and the difference between the two buys you the rest of the property for the day. If you're local and you're coming once a week on your way home from work, the hourly rate is what you want.
PLAN YOUR VISIT
How far in advance should you book Harmony Point?
It’s a wood-fired sauna (with space for 12) and three tubs (with space for 4 people each), and twelve total is what fits. Call ahead the day before and you’ll almost always get the hour you want. Same-day is usually fine too. The hours that go first are late afternoon and sunset for obvious reasons. If you are coming for that, give us a couple of days. Mornings are wide open and are genuinely better for the circuit anyway, since you’ve got the rest of the day in front of you instead of a dinner reservation in 40 minutes.
If you’re staying here, the best move is to book your Harmony Point hour at the same time you book your water sports. Do your kite session or e-foiling in the morning, eat, then take your hour in the afternoon. That’s the day this was built for.
If your hour is taken, take one on either side. The sauna doesn’t care what time it is.
AFTER THE HOUR
What should you drink after a sauna session?
Water, first. You’ve been sweating for most of an hour, and the plunge makes you feel fine, so most people forget to drink.
Bring your own bottle. There's no outside food or drink at Harmony Point, but a water bottle is the exception and we'd rather you had one.
The market on property stocks a rotating set of packaged drinks, and the staff out there will point you in the right direction if you have questions.
If you're here for recovery and inflammation, you want the ginger, turmeric, and cucumber end of the shelf. If you just finished three rounds and you're wrung out, electrolytes.
Skip the alcohol for a couple of hours.
THE FIT
Who shouldn’t book the sauna and cold plunge?
Looking for a spa?
If you're looking for a spa, this isn't one. No massage, no treatments, no robes, no quiet room with cucumber water. Harmony Point is closer to training rather than to pampering. There are proper spas in the Keys and we're happy to point you toward one. Just ask the front desk.
Looking for solitude?
If you want to be alone, think about the timing. You'll potentially be sharing the sauna and the tubs with up to eleven other people.If solitude is the whole point for you, book the first hour of the day and you'll likely have a lot more room.
Can I use the Sauna and Cold Plunge if I’m pregnant?
If you're pregnant, this isn't the activity. Extreme heat and cold swings aren't appropriate during pregnancy. We won't make an exception on it.
Can I use the Sauna and Cold Plunge if I have been drinking?
If you've had anything to drink, or you're on something, come back tomorrow. Alcohol and drugs do not mix with 190-degree heat and 40-degree water, and the staff out there will turn you away.
If you have a heart condition, blood pressure issues, or anything cardiovascular going on, talk to your doctor first. The whole circuit works by spiking and dropping your heart rate three times in an hour.
For most people it's a good stress and for some people it isn't, and we're not the ones qualified to tell you which.
You'll sign a waiver either way.
FAQ
Questions about Harmony Point
Book Your Hour at Harmony Point
Staying with us? It’s in your resort fee. Book your hour at the front desk when you book your water sports, and plan it for the afternoon after your session.
Not staying with us? $35 gets you an hour of sauna, cold plunge, and the outdoor fitness area. Mornings are wide open. Sunset goes first.