Deepline: Apnea & Freedive

Find your breath. Deepline pairs a calm apnea trainer — CO2 and O2 tables plus box breathing — with a beautiful freediving logbook. Fully offline. The numbers are the heroes, and the water goes still when you hold.

Deepline is for freedivers, spearfishers and snorkelers — and for anyone who wants a quieter way to train their breath.

Train your breath hold
- CO2 and O2 apnea tables, auto-built from your personal max
- Box breathing for daily calm and pre-dive focus
- A still, high-contrast timer made for wet hands and bright sun
- The water stays motionless during every hold — nothing to distract you

Log every dive
- Depth, breath-hold time, discipline and conditions
- A GPS pin for every spot
- Your full freediving logbook, kept on your device

See your progress
- Watch your breath-hold time grow, session after session
- Personal records, kept simple

Calm by design
- A signature living-water interface, not another stopwatch
- No clutter, no noise, no emoji
- Works fully offline — no account, no sign-up, your data stays yours

How it works
1. Measure your baseline breath hold
2. Train with CO2 / O2 tables and box breathing
3. Log your dives and watch your progress deepen

Not a medical device. Deepline does not measure anything with the iPhone itself: pulse and SpO₂ come only from an external Bluetooth sensor you choose or from Apple Health. Readings are not intended for diagnosis, treatment, medical decisions, or monitoring the safety of a breath hold. Deepline is designed for general fitness and wellness purposes only and is not intended to diagnose, treat, cure, monitor or prevent any disease or medical condition. Pulse and SpO₂ come from your own sensor or Apple Health and are shown for training only. Always talk to your doctor before starting breath-hold training and before making any medical decisions. Never train breath-holds in or near water without a trained buddy.

Free to use. Your breath, your data, your line to the deep.