Decathlon Fit 100 review: budget sports watch with AMOLED, GPS and stress tracking

A low-cost sports watch with a vivid AMOLED display, integrated GPS and stress monitoring seems almost too ambitious at this price.

Decathlon believes it has found the answer: a fitness smartwatch with close to a full set of features for under €70, designed for occasional runners and daily wearers who still expect “proper” tracking. Having worn the new Fit 100 for several weeks, the issue is not merely what it offers, but which compromises were necessary to reach this price.

What Decathlon is offering with the Fit 100

The Fit 100 is Decathlon’s latest own-brand smartwatch, costing €69.99 (around $75). Positioned beneath the brand’s more dedicated GPS watches developed with Coros, it is aimed at people wanting health information, step tracking and notifications without spending Apple Watch-level money.

AMOLED screen, multi‑GNSS GPS, heart‑rate and SpO2 sensors, 5 ATM water resistance and a week‑long battery - all under €70.

Its specification sheet appears unusually generous for this segment:

A recognisable design with no attempt to hide it

From a distance, the Fit 100 strongly resembles an Apple Watch, with its rectangular body, curved corners, right-side digital crown and black-only colourway. Its casing is plastic finished to resemble aluminium, meaning it lacks the cool feel of metal; look carefully and the join between its sides and base is apparent.

The TPU strap is perfectly adequate, if unremarkable. More positively, its quick-release pins allow a third-party band to be fitted in seconds, rather than locking users into the supplied styling.

At 90 g including the strap, it is relatively heavy beside many fitness watches, although it remains comfortable to wear. It is also manageable to keep on overnight for anyone tracking sleep data.

With a 5 ATM rating, the Fit 100 can be used for swimming, pool workouts and open-water sessions. However, Decathlon advises against wearing it in hot showers or saunas, as heat and steam can put pressure on seals in less expensive cases.

Fit 100 AMOLED display: making budget watches seem old-fashioned

The 1.97-inch AMOLED screen is the product’s standout feature. Colours are vibrant, blacks look properly deep, and information remains easy to read even with several metrics squeezed onto a single display. Its 390 × 450-pixel resolution provides crisp text and icons.

Brightness outdoors is better than expected. Although it cannot match the eye-searing output of the newest Apple Watch or Pixel Watch, the display remained readable on sunny runs without repeatedly turning the wrist to find a better angle.

The Fit 100’s display looks closer to a mid‑range smartwatch than a bargain‑bin tracker, and that changes how it feels on the wrist.

An always-on setting is available, leaving a simplified watch face permanently visible. Enabling it cuts battery endurance by around half. At this price and with this battery capacity, that is an inevitable compromise.

Straightforward software that avoids unnecessary complexity

Controls combine touchscreen swipes with the rotating crown. Swiping down opens notifications, swiping up reveals quick settings including brightness and do-not-disturb, while sideways swipes move through widgets for daily steps, heart rate and weather. A crown press opens the app grid or returns to the watch face.

Rather than Wear OS or another open ecosystem, Decathlon has opted for its own operating system. This makes operation quick and uniform on Android and iOS, but has one major limitation: third-party apps are unavailable.

The Fit 100 is designed to stay basic on purpose, trimming features so new users aren’t buried under menus and settings.

There are therefore no Spotify downloads, on-wrist Google Maps or meditation applications. Instead, it focuses on activity monitoring, health measures and notifications, which will probably cover the requirements of Decathlon’s intended buyers.

Decathlon Hub: the companion app behind the watch

More detailed insights are handled in Decathlon Hub, the companion app for Android and iOS. This is where sports profiles are adjusted, data pages are personalised and training records can be reviewed.

Its uncluttered dashboard shows daily movement, sleep charts, resting heart rate and stress patterns. It is slightly more functional than polished compared with Garmin Connect or Apple Health, but it includes the essential information.

• Automatic sync of workouts to Strava
• Configuration of up to ~50 sports profiles
• Custom data screens per sport
• Sleep and stress history with basic trends

Synchronisation from phone to watch can occasionally be slow, especially after a longer run. Activity launch on the watch itself is still rapid, though, which is arguably more important immediately before exercise.

Sports tracking: an impressive list with inconsistent accuracy

The watch includes 14 sports modes as standard: running, cycling, walking, strength training, pool swim, open-water swim, rowing, treadmill, hiking and others. Through the app, this can be expanded to roughly 50 profiles, although many use comparable metrics with altered labels.

While exercising, users can view time, distance, pace or speed, heart rate, calories and other data. Fields can be tailored, letting runners put pace and lap time first, whereas gym users may favour heart rate and session duration.

Its multi‑GNSS GPS chip is among its key selling points. Satellite connections are obtained quickly, often within a few seconds, avoiding the need to wander around a car park awaiting a signal. This is a meaningful benefit for people fitting workouts into their lunch break.

Accuracy, however, is where its budget origins become evident. In one notable test, the Fit 100 recorded only 17.8 km during a 20 km officially measured Paris race, a discrepancy of around 11%. Later assessment indicated that GPS had not activated at all, and that distance was probably calculated from steps and arm movement. This is a fault rather than normal operation, but it highlights the limitations of firmware on a new product.

For casual tracking the GPS is acceptable; for pace‑sensitive training plans or race prep, that kind of glitch is a serious red flag.

On other runs, recorded distance was within the typical 1–3% variation expected from entry-level GPS watches. Even so, serious runners managing interval sessions and race-pace work are likely to prefer a more proven platform.

How Decathlon tests a €70 smartwatch

Decathlon subjects the Fit 100 to two principal stages of testing. Laboratory work concentrates on durability and ageing, including waterproofing inspections, button-press cycles, UV exposure, extreme-temperature chambers and strap-pull assessments. These tests are intended to identify early hardware faults before units arrive in shops.

Field testing then gives watches to internal teams and external testers through co-creation programmes. Attention turns to GPS operation, heart-rate results and swimming data in actual conditions. This also explains why the severe GPS issue described above was not caught in routine validation: unusual cases can still pass through even organised testing processes.

Heart rate, sleep and stress: sufficient for most users

The optical heart-rate sensor works continuously, recording pulse data day and night. During rest and steady activity, such as easy runs, extended walks and gentle cycling, results broadly align with expectations and reference devices.

It has greater difficulty with intervals and brief high-effort bursts. Heart-rate peaks can appear a few seconds late, while some intense surges are averaged out. This is common for wrist sensors in this category, but it reduces its usefulness for athletes closely examining heart-rate zones.

Pairing a separate Bluetooth chest strap remains the better option for anyone training with strict heart‑rate targets.

Blood oxygen (SpO2) readings are chiefly a wellness feature. They may reveal patterns when a user is run-down or at altitude, but wrist-based technology is not sufficiently precise to serve as a medical reference.

Sleep monitoring operates automatically. It records overall sleep time, estimates light, deep and REM stages, and identifies wake-ups. Start and finish times generally correspond with what users remember. Stage estimates should be considered approximate rather than definitive, as is the case with most consumer sleep trackers rather than this device alone.

Stress scores are calculated from heart-rate variability, which measures the extent to which heart rate changes between beats. The Fit 100 converts this into a daily stress graph and may prompt guided breathing exercises when levels rise. It is a cue to take a break rather than a scientific diagnosis, but can be useful during demanding days.

Smart functions: only the essentials survived

For connected features, the Fit 100 stays with the basics. It receives notifications for calls, text messages, emails and apps, and Bluetooth allows calls to be answered when the phone is nearby. Sound quality is acceptable for brief conversations.

Several prominent omissions help explain the price. There is no NFC chip, ruling out wrist payments after a run. It offers neither offline music storage nor streaming-app controls. Voice assistants are missing, and its closed software system prevents extra apps from being added later.

The Fit 100 behaves more like a robust fitness tracker with a big, bright screen than a full smartwatch replacement.

Battery life that rivals much more expensive devices

Decathlon states that the watch can run for up to seven days with “normal” use, including continuous daily tracking, notifications and several weekly workouts. Testing suggests six to seven days is achievable when the always-on display is switched off.

With always-on mode enabled, endurance falls to around three or four days, which remains respectable at this cost. In continuous GPS mode, it lasts approximately eight hours. That is enough for most road races, urban marathons and lengthy weekend rides, but not for multi-day hikes or ultra-distance competitions.

A proprietary magnetic cable is used for charging, with an empty battery taking around two hours to reach full capacity. It is not rapid charging, but a week between charges for most owners makes this manageable.

The Fit 100 in Decathlon’s longer-term strategy

Within Decathlon’s product structure, model numbers broadly indicate capability: “100” denotes entry level, “500” intermediate and “900” advanced. The Fit 100 is clearly an initial step in a wider smartwatch range rather than an isolated experiment.

This points towards a probable plan for a later Fit 500 with additions such as improved GPS or payments, followed by a Fit 900 positioned closer to today’s Coros-powered GPS900 for dedicated endurance athletes. For buyers, this division is relevant because it shows Decathlon is not attempting to place every feature into its first model; instead, it is creating a device range for varying requirements.

How to decide whether the Fit 100 is enough

For modest aims - hitting 10,000 steps, recording a few weekly runs, gaining an overview of sleep quality and avoiding the need to constantly reach for a phone - the Fit 100 covers most needs. Inaccuracies seen during races or interval work will matter less to anyone interested in general activity and approximate distance rather than precise splits.

For people preparing for their first 5K or 10K, it can remain an effective motivational tool. Watching distance gradually rise, seeing heart rate decline over comparable runs, or building weekly totals offers clear evidence of progress, even if every metre is not measured exactly. The important point is to view its data as indicative rather than laboratory-grade.

Anyone following a structured programme with pace targets and defined zones, or pursuing a Boston qualifier, should regard this watch more as a backup option. A dedicated GPS device with dependable distance recording and detailed workout export would be more suitable.

Terms and compromises worth knowing

Two technical expressions appear often in discussion of the Fit 100: “multi‑GNSS” and “single‑frequency GPS”. Multi‑GNSS means the watch can draw on multiple satellite networks - usually GPS (US), GLONASS (Russia) and others such as Galileo (EU). Compared with GPS alone, this can improve coverage in urban areas and woodland.

Single-frequency means that it receives only one radio-frequency band from these satellite systems. More expensive devices can receive two, often known as L1 and L5, helping them filter reflections from high-rise buildings and limit drift. This is one reason premium watches map routes more accurately around skyscrapers and along winding trails.

Optical heart-rate sensors also require some context. They project light into the skin and detect minute reflection changes as blood pulses through vessels. Movement, tattoos, skin tone and strap tightness can all influence the results. Anyone heavily dependent on heart-rate zones - including users on polarised training plans - should use wrist data as guidance and consider a chest strap for important sessions.