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