Built for people who hold their breath.
Every session happens on land, seated or lying down. Never in the water.
Freediving
Dry CO₂ and O₂ tables at home, between days in the water.
Spearfishing
Learn to stay calm as the urge to breathe builds, trained on land.
Surfing
Get used to the urge to breathe on land, not in a hold-down.
Breathwork
Structured, paced breath-holds with haptic cues, eyes closed.
Your wrist is the
whole app.
Most apnea apps treat the watch as a remote. Holdfast runs the entire session from your wrist — screen dark, eyes closed, phone in another room. Just the haptics and your breath.
A rhythm you can feel.
Each phase has its own haptic cue: a rising tap to inhale, a firm start to the hold with a soft tick while it runs, a double tap to exhale, and a countdown in the last three seconds. Learn them once and you can keep your eyes closed through the whole table.
Watch your tolerance grow.
Streaks, personal bests, a month calendar, and a six-week max-hold chart. Turn on Apple Health and every session is saved as mindful minutes.
No account. No network. No tracking.
Every table, the breath check, your history and your Apple Watch sessions work with airplane mode on. Nothing to sign up for, and your training stays on your iPhone and Apple Watch.
Two tables, two adaptations.
CO₂ tables teach you to stay calm as the urge to breathe rises. O₂ tables stretch how long you can hold. Take one relaxed, seated breath check and Holdfast sizes both tables from the result — or start from the standard tables.
The hold stays the same length while rest shrinks each cycle. You start every hold with more CO₂ on board — and learn to stay relaxed through the urge to breathe.
Rest stays constant while the hold grows each cycle. You teach your body to do more with less oxygen — extending your comfortable maximum hold over time.
Free forever. Premium when you want more.
No ads. No dark patterns. The core trainer is free for good.
Premium is monthly, yearly, or a one-time Lifetime purchase. The app shows the price in your currency.
Questions, answered.
Is it safe?
Holdfast is for dry training only: seated or lying down, on land. Never practice breath-holds in or near water alone, and don’t hyperventilate before a hold. Shallow-water blackout gives no warning, and CO₂ tolerance does not protect you from it. Stop if you feel dizzy or unwell. Holdfast is a training aid, not a substitute for proper freediving instruction.
Do I need an Apple Watch?
No. Every table runs on iPhone alone. With an Apple Watch, sessions run on your wrist with the screen off and a haptic cue for each phase, and the watch reads your heart rate live.
What’s free?
The breath check, personalized and standard CO₂ and O₂ tables, Apple Watch sessions with haptics and live heart rate, your history and personal bests, and share cards. No ads, and no time limit.
What does Premium add?
Multi-week programs, the custom table builder, and advanced analytics. Premium is a monthly or yearly subscription, or a one-time Lifetime purchase, and the app shows the price in your local currency. If a subscription ends, your tables and history stay, and an active program pauses until you come back.
Does it work offline?
Yes. Tables, the breath check, your history and Apple Watch sessions all work in airplane mode, and there’s no account to create. You only need a connection to buy or restore Premium.
Which languages?
English and Spanish. The app follows your iPhone’s language setting.
More on the support page.
Never practice breath-holds in or near water alone — shallow-water blackout gives no warning. No hyperventilation. Stop immediately if you feel dizzy or unwell. Holdfast is a training aid, not a substitute for proper freediving instruction.