1-tap multi-lane wave starts
Sending 3 swimmers per lane off in waves? One tap on Start wave launches the next eligible swimmer across every lane at the exact same millisecond — even while earlier waves are still swimming.
🏊 Built for SCY, SCM, and LCM pool decks
Stop juggling stopwatches and soggy clipboards.
SeshTimer turns any iPad or Android tablet into a rugged, multi-lane swim timing command center. Launch synchronized waves across 8 lanes, capture 25/50/100 splits with wet fingers, and share live leaderboards and Excel reports before your swimmers finish toweling off.
0.01s
Monotonic clock precision
25 yd / 50 m
Native SCY, SCM, and LCM math
100% offline
Dead-zone pool Wi-Fi resilient
Coaching eyes on the water, not on paper
Designed around real pool-deck chaos
Whether you’re running a 6:00 AM high school varsity threshold set, an NCAA sprint test, or a USA Swimming senior practice, SeshTimer removes the friction between timing and coaching.
Wet-finger proof tablet interface
Oversized 56px–68px buttons, zero scrollbars, and accidental touch protection: tapping a swimmer’s name or card background never triggers a false split. Plus, every card has its own independent Undo button.
Offline-first natatorium sync
Concrete pool decks are notorious Wi-Fi dead zones. SeshTimer queues every split locally in IndexedDB with zero lag and automatically syncs to the cloud the moment your tablet reconnects.
Native SCY, SCM, and LCM engine
Seamlessly switch between 25-yard winter short course and 50-meter summer long course. SeshTimer calculates exact pool lengths, intermediate splits, and exact yard-to-meter conversions automatically.
Target cutoffs and season charts
Set men’s, women’s, or general target times per exercise. View instant leaderboards with target cutoff dividers, horizontal comparison bars, and individual athlete progression curves across the season.
Public athlete portal and staff sync
Link assistant coaches’ emails so your entire staff shares one live roster, and generate a read-only public stats link so swimmers and parents can check personal bests without logging in.
Visual tour
Every screen built for speed on the pool deck
Select any screen below, tap the numbered hotspot pins (1–4) to inspect coach-specific interface details, or tap the tablet screen to open the full-resolution zoom view.
All 6 coaching screens at a glance
Tap any card below to inspect it in full-screen high resolution:
Under the hood
Engineered specifically for competitive swimming
Generic fitness timers fail on the pool deck. SeshTimer’s timing engine and data model were built around how swim coaches actually structure sets, lanes, and intervals.
Drift-free monotonic timing engine
SeshTimer never sums interval timer ticks. Every split and finish is computed by subtracting monotonic high-resolution hardware timestamps (`performance.now()`), completely decoupled from UI rendering frames.
Configurable countdown and start horn
Enable a 1–30 second visual and audible WebAudio countdown before each wave start so swimmers on the blocks or pushing off the wall get consistent acoustic cadence cues.
Compound distances and bulkhead pools
Whether you’re running broken 200s (`8x25`), standard `100 yd` repeats, or training in a `33⅓ m` bulkhead pool, SeshTimer tracks exact length progressions and intermediate split milestones.
Accidental double-tap debouncing
Water droplets and quick taps at the finish wall won’t ruin your data. Start-to-finish debouncing blocks instant accidental double taps, and card surfaces outside action buttons are non-interactive.
Multi-coach workspace linking
Head coaches can link assistant coaches’ email addresses in settings. Assistants sign in with passwordless 6-digit email codes and immediately access the shared team roster, workouts, and results.
Complete JSON backup and Excel export
Your program owns 100% of its data. Export single workouts or full-season databases to `.xlsx` Excel spreadsheets, or create full idempotent JSON backups for season-to-season archiving.
Side-by-side comparison
Why swim programs upgrade to SeshTimer
See how SeshTimer compares against traditional multi-stopwatch clipboard timing and generic stopwatch apps.
| Poolside capability | SeshTimer (tablet app) | Stopwatch + paper clipboard | Generic stopwatch apps |
|---|---|---|---|
| Multi-lane wave starts | ✅ 1-tap simultaneous wave launch across all lanes | ❌ Manual mental math subtraction (:05 / :10) | ❌ Single timer or ungrouped list |
| Intermediate 25/50 splits | ✅ Stored per swimmer, per set and rep automatically | ❌ Impossible to write down while watching turns | ⚠️ Overwrites or loses lane context |
| Wet-finger mistake recovery | ✅ Independent per-swimmer undo + inline edit history | ❌ Ruined rep or missed watch reset | ❌ Resets entire heat |
| Pool Wi-Fi dead zones | ✅ 100% offline IndexedDB queue + auto cloud sync | ⚠️ Paper gets soaked; manual typing later | ⚠️ Often loses unsaved session state |
| Post-practice Excel & parent sharing | ✅ Instant .xlsx export & 1-click public stats URL | ❌ 45+ minutes of typing into spreadsheets | ❌ Raw CSV text dump only |
Time-saved calculator
How much deck and office time will your staff save?
Adjust the sliders for your swim program to see how many hours of manual clipboard transcription and how many thousands of splits SeshTimer automates per season.
56 hrs
Coaching office hours saved
Zero manual spreadsheet typing after morning or afternoon practices.
73,728
Precision splits captured
Automatically indexed by swimmer, stroke, pool length, and date.
Quick answer
What is SeshTimer and how does it work?
SeshTimer is a tablet-first web app that replaces stopwatches and clipboards for swim coaches. It times multi-lane wave starts, records splits for every swimmer, keeps working offline on the pool deck, and turns each practice into leaderboards, target-cutoff charts, shareable stats links, and Excel reports. It runs in any modern browser on iPad, Android tablets, and laptops, and can be installed like an app.
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Open the app
Go to go.seshtimer.app and sign in with a one-time code sent to your email. No password needed.
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Build the workout
Pick the pool (SCY, SCM, LCM, or a custom length), the set (for example 4 × 100), and your swimmers or groups. Lanes are assigned automatically.
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Start waves
Tap Start wave to send off the next swimmer in every lane at once, with an optional countdown and start horn.
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Record splits and finishes
Tap Split at each wall and Finish at the end. Made a mistake? Undo fixes just that swimmer.
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Review and share
See leaderboards and target cutoffs, export to Excel, or text parents a read-only public stats link.
- Best for
- Club, high school, college, and masters swim coaches
- Devices
- iPad, Android tablets, Windows, macOS, ChromeOS (browser or installed app)
- Pools
- 25 yd (SCY), 25 m (SCM), 50 m (LCM), and custom lengths like 33⅓ m
- Offline
- Yes, results are queued on the device and synced automatically
- Languages
- English (US, British, and Australian date formats) and Hungarian
- Made by
- ATN
Coach FAQ
Everything swim coaches ask before stepping on deck
Got questions about tablets, offline natatoriums, or yard and meter conversions? Here are the answers.
Your timing board never skips a beat. SeshTimer stores your active workout state and every recorded
split in a durable local IndexedDB queue on your tablet. As soon as your tablet reconnects to Wi-Fi in
the coach’s office, SeshTimer automatically replays and syncs every result to the server with strict
UUID idempotency.
Yes. You can define unlimited pools in your library in either yards (`yd`) or meters (`m`), including
25 yd, 25 m, 50 m, or custom bulkhead lengths like 33⅓ m. If an exercise distance and pool length use
different units, SeshTimer performs exact conversion (`1 yd = 0.9144 m`) automatically.
First, tapping a swimmer’s name or card background does nothing — only the large, color-coded `START`,
`SPLIT`, and `FINISH` buttons trigger timing events. Second, every swimmer card features an independent
Undo button that reverts only that swimmer’s last action (`start`, `split`, or
`finish`) without affecting any other swimmer in the pool.
On the statistics page, tap Create public statistics link. You’ll get a customizable,
read-only URL (with optional default theme and language settings) that you can text or email to athletes
and parents. No login is required to view it, and you can revoke and regenerate the link at any time.
Yes. Under Settings → Shared accounts & access, assign your assistant coaches’
email addresses. When they sign in with their email one-time code, they automatically share your team’s
swimmer roster, groups, exercises, workouts, and results.