Plunge app alternatives for tracking your sessions
Keep the Plunge app for running the tub. It sets the temperature and controls the chiller, which no tracking app can do. If what you want from it is a record of your sessions, Contrast does that part on its own: it starts the round when you get in on an Apple Watch Ultra or Series 10 and later, saves every session to Apple Health, keeps its own copy on your phone, and has no account to be logged out of.
Side by side
| Plunge | Contrast | |
|---|---|---|
| Controls the tub | Yes | No |
| Records sessions | Yes | Yes |
| Starts a round when you get in | Not advertised | On Apple Watch Ultra or Series 10+ |
| Water temperature | From the tub | From the watch, in six bands |
| Saves to Apple Health | Not advertised | Yes, as a Cooldown workout |
| Works with other tubs | Built for Plunge products | Any tub, barrel or bath |
| Price | Free (the tub is sold separately) | Free, with optional Pro |
Plunge column from its App Store listing, checked 2 October 2026. "Not advertised" means the listing does not mention it, not that the app cannot do it.
What Plunge does
- Controls Plunge cold plunges and saunas from your phone, including the water temperature.
- Times cold plunge and sauna sessions and shows how many you do and how often.
- Has an Apple Watch app.
What its low-star reviews keep raising
Recurring themes in its 1–3 star App Store reviews, paraphrased rather than quoted. Each review is one person's experience, and some will describe problems since fixed.
- Being signed out repeatedly and having to log back in before a session.
- Sessions, or months of history, disappearing after an update or a crash.
- No export to Apple Health.
- No way to backdate a session or add one that failed to save.
- One user per tub, so a second person in the house cannot keep a history of their own.
Many low-star reviews of this app are about the tub itself: chillers, leaks and support. Those are about the hardware, not the tracking, and are left out here.
Where Contrast is different
- It works with any tub, a Plunge included. The watch reads the water rather than the tub's display.
- There is no account, so there is nothing to be signed out of.
- Every session is saved to Apple Health as a workout, and Contrast keeps its own copy on the phone as well.
- A session you forgot to start can be logged on the iPhone afterwards, with its rounds and temperatures.
- Each person uses their own phone and watch, so a household keeps separate histories without sharing a login.
Stay with Plunge if
- You want one app that both runs the tub and logs your sessions. Contrast only does the second, and has no connection to the tub at all.
- You want to set the temperature, schedule a cool-down or control the chiller and lights. Only the Plunge app does that.
Common questions
Can I use Contrast with a Plunge tub?
Yes. Contrast reads the water through an Apple Watch Ultra or Series 10 and later rather than talking to the tub, so it works with a Plunge, any other tub, an ice barrel or a bath. Keep the Plunge app for controlling the tub.
Does Contrast control the Plunge chiller or temperature?
No. It has no connection to the tub. Use the Plunge app for that, and Contrast for the record.
Contrast is not affiliated with Plunge - Official App or Reboot Labs, LLC.. Their name is used here only to identify their app.