The answer — one pick, priced
Get the
Fitbit Charge 6
$30 under your budget
The cheapest credible swim tracker here — 5ATM with a dedicated swim mode and 7-day battery, in a band slim enough that you never take it off.
Fit ledger — need → measured evidence
■ The catch — co-equal billing, always
It counts your laps, it does not read your swimming. No stroke type, no SWOLF, limited in-water HR — for technique data you need a Garmin or the FORM goggles. The price is soft too: it has swung between $89 and $160 this year, so $120 today can look expensive six weeks from now. Watch it before you commit.
Dealbreaker? Runner-up №1 buys real in-water heart rate for $15 less ↓
■ Every product has a catch. Verdicts that hide it are how bad buys happen.
Don't buy this if…
- you want a general running or multisport watch without swim focusGPS running watch verdict →
- you want a general smartwatch for everyday use, not swim-focusedSmartwatch verdict →
- you want a chest-strap heart rate sensor rather than a swim trackerHeart rate chest strap verdict →
Wrong product for you is still a bad buy. These are the cases where we'd send you somewhere else.
Runners-up — if your needs differ
Adjacent verdicts — other needs, same method
Different budget, different household, different job — each of these is already researched, priced and verified. Take the one that matches your need.
Traps — this verdict avoids
Why the Fitbit Charge 6 is right for you
It avoids every trap below — and for just me, under $150, it is the pick because it delivers:
IPX7 is not swim-proof
IPX7 means splash and brief immersion — it is never safe for swimming, and it is the rating most cheap "waterproof" trackers quote. 5ATM / WR50 is the pool minimum, 10ATM / WR100 covers surface water sports, and EN13319 is the dive-accessory standard a depth gauge needs. Every rating assumes a factory-sealed watch: a battery swap or a damaged case voids it.
Your wrist cannot read your heart rate underwater
Optical HR accuracy falls apart above 140 bpm and on any stroke with wrist flexion — breaststroke and butterfly especially. No wrist-worn watch on this card is trustworthy for in-water zones. The fix is a sensor that is not on your wrist: a Polar Verity Sense armband at $105 on the upper arm or clipped to a goggle strap, FORM's temple sensor, or a swim-rated chest strap.
The retired model costs more than its replacement
Garmin retired the Swim 2 in May 2025 and never shipped a successor — remaining listings are third-party leftovers, and there is no dedicated swim watch left to buy. The same trap runs current: leftover Apple Watch Ultra 2 stock sits at $782 while the current Ultra 3 is $700, and Polar Ignite 3 stock still asks ~$400. Check that the model you are about to buy is the one still in production.
Provenance — 10 sources, dated
Winners are picked from the full research dossier at knowledgelib.io. Prices, stock and listings are re-verified monthly.