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Wearable comparison

Samsung Galaxy Watch 9 40mm vs OnePlus Watch 4

Compare battery life, health tracking, display and fit.

Compared products
01Selected
Samsung Galaxy Watch 9 40mm

Samsung Galaxy Watch 9 40mm

  • Screen: 44 mm: 480 × 480 pixels; 40 mm: 438 × 438 pixels.
  • Qualcomm Snapdragon Wear Elite, 3 nm processor.
  • 2 GB RAM in this version.
  • 32 GB storage in this version.
  • Runs Wear OS 7; One UI 9 Watch.
KSh 39,500In Stock
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02
OnePlus Watch 4

OnePlus Watch 4

  • Screen: 466 × 466 pixels; 310 ppi.
  • Qualcomm Snapdragon W5; BES2800 MCU processor.
  • 2 GB RAM in this version.
  • 32 GB storage in this version.
  • Runs OxygenOS Watch 8; Wear OS 6.0.
KSh 38,500In Stock
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2 spaces available

Samsung Galaxy Watch 9 44mmKSh 42,000
Samsung Galaxy Watch UltraKSh 45,000
Google Pixel Watch 3KSh 37,500
Samsung Galaxy Watch 8 ClassicKSh 38,500
Samsung Galaxy Watch Ultra 2025KSh 44,000
Amazfit Balance 2KSh 39,000
Google Pixel Watch 5 41mmKSh 42,000
2 of 4 products

Our quick verdict

The Samsung Galaxy Watch 9 40mm takes ECG heart-rhythm readings, is lighter to wear all day and has a cellular option for calls without your phone, while the OnePlus Watch 4 lasts longer between charges (up to 5 days) and has a premium titanium build.

Display

Samsung Galaxy Watch 9 40mm
44 mm: 480 × 480 pixels; 40 mm: 438 × 438 pixels
OnePlus Watch 4
466 × 466 pixels; 310 ppi

Performance

Samsung Galaxy Watch 9 40mm
Qualcomm Snapdragon Wear Elite, 3 nm processor
OnePlus Watch 4
Qualcomm Snapdragon W5; BES2800 MCU processor

Software

Samsung Galaxy Watch 9 40mm
Runs Wear OS 7; One UI 9 Watch
OnePlus Watch 4
Runs OxygenOS Watch 8; Wear OS 6.0

Connections

Samsung Galaxy Watch 9 40mm
Bluetooth 5.3 connection
OnePlus Watch 4
Bluetooth 5.2 connection

Battery life

Samsung Galaxy Watch 9 40mm
Up to 30 hours per charge
OnePlus Watch 4
646 mAh battery

Key differences

The main differences to help you choose.

Samsung Galaxy Watch 9 40mm

  • Lighter: 31.5 g (vs 68 g).
  • ECG heart-rhythm readings.
  • eSIM.
  • Cellular option (LTE/5G models) for calls and data without your phone.
  • Slimmer: 8.6 mm thick (vs 11 mm).

OnePlus Watch 4

  • Longer rated battery life: up to 5 days (vs 30 hours).
  • Titanium case (vs aluminium case).
  • Lower price: KSh 38,500 (vs KSh 39,500).

What matters most to you?

Choose any priorities

How each product answers the questions buyers ask most. Tick a topic to add it, untick one to hide it.

More topicsFewer topics
6 priorities selected.
How each product answers the selected priorities
PrioritySamsung Galaxy Watch 9 40mmOnePlus Watch 4
Battery lifeUp to 30 hours per charge646 mAh battery
Storage32 GB storage32 GB storage
Display1.47-inch OLED display1.5-inch OLED display, 310 ppi
PerformanceQualcomm Snapdragon Wear Elite processorQualcomm Snapdragon W5 processor
SoftwareWear OS 7OxygenOS Watch 8
ConnectionsBluetooth 5.3Bluetooth 5.2

Detailed comparison

Explore the full specifications, section by section.

Display

Display specifications comparison
SpecificationSamsung Galaxy Watch 9 40mmOnePlus Watch 4
Display44 mm: 1.47-inch Super AMOLED; 40 mm: 1.34-inch Super AMOLED1.5-inch LTPO OLED
Screen resolution44 mm: 480 × 480 pixels; 40 mm: 438 × 438 pixels466 × 466 pixels; 310 ppi
Display protectionSapphire crystalSapphire crystal
Display features3000 nits (peak)600 nits (typ), 1600 nits (HBM), 3000 nits (peak)

Connectivity

Connectivity specifications comparison
SpecificationSamsung Galaxy Watch 9 40mmOnePlus Watch 4
Network / cellularGSM / HSPA / LTENo cellular connectivity
SIM / eSIMeSIMUnsupported
Wi-FiWi-Fi 2.4 GHz + 5 GHzWi-Fi 2.4 GHz + 5 GHz
BluetoothBluetooth 5.3Bluetooth 5.2
NFCSupportedSupported
Positioning / GNSSDual-frequency GPS, L1 + L5Dual-frequency L1 + L5; GPS; BeiDou; Galileo; GLONASS; QZSS

Identity & design

Identity & design specifications comparison
SpecificationSamsung Galaxy Watch 9 40mmOnePlus Watch 4
BrandSamsungOnePlus
ModelSamsung Galaxy Watch 9 (40 mm and 44 mm configurations)OnePlus Watch 4
Announced2026, July 222026, April 22
Dimensions44 mm: 46.0 × 43.7 × 8.6 mm; 40 mm: 42.7 × 40.4 × 8.6 mm47.4 × 47.4 × 11.0 mm
Weight44 mm: 34.0 g; 40 mm: 31.5 g, without bandApproximately 43 g without strap; 68 g with strap
Build materialsAluminum caseTitanium-alloy case; PA and fibreglass back
Strap / bandLightweight breathable Sport Band with Dynamic Lug SystemFluororubber
Controls / buttonsTouchscreen and two side buttons—
Wrist size—140–210 mm

Performance & software

Performance & software specifications comparison
SpecificationSamsung Galaxy Watch 9 40mmOnePlus Watch 4
ProcessorQualcomm Snapdragon Wear Elite, 3 nmQualcomm Snapdragon W5; BES2800 MCU
CPU5-core—
RAM2 GB2 GB
Storage32 GB32 GB
Operating systemWear OS 7; One UI 9 WatchOxygenOS Watch 8; Wear OS 6.0

Audio & communication

Audio & communication specifications comparison
SpecificationSamsung Galaxy Watch 9 40mmOnePlus Watch 4
SpeakerSupportedSupported
MicrophoneSupportedSupported
CallingBluetooth calling with a connected smartphone; standalone calling on LTE editionsBluetooth calling with a connected smartphone

Sensors, health & fitness

Sensors, health & fitness specifications comparison
SpecificationSamsung Galaxy Watch 9 40mmOnePlus Watch 4
SensorsSamsung BioActive: optical heart-rate, electrical heart signal, bioelectrical impedance analysis; temperature; accelerometer; barometer; gyroscope; geomagnetic; light sensorAccelerometer; gyroscope; optical heart-rate sensor; optical blood-oxygen sensor; geomagnetic sensor; ambient-light sensor; barometer; wrist-temperature sensor
Health & wellness featuresHeart rate; SpO₂; ECG; body composition; temperature; stress; Vitals; Heart Health ScoreHeart rate; high and low heart-rate alerts; SpO₂ spot checks and all-day monitoring; stress; breathing exercises; cycle tracking; 60-second Wellness Overview
Sleep trackingSleep-stage tracking; sleep-apnea risk detection; sleep VitalsDeep, light and REM sleep; awake time; sleep score; breathing rate; SpO₂; snoring-risk assessment
Sports / workout modesAutomatic and manual workout tracking across running, walking, cycling, swimming and other activities100+ sports modes
Training & outdoor featuresDaily Cardio Load; Fitness Index; workout and recovery guidanceAerobic training effect; cardiorespiratory capacity; recovery time; heart-rate recovery; running form; track running
Safety & emergency featuresFall detection and Emergency SOSFall detection; emergency rescue

Battery & durability

Battery & durability specifications comparison
SpecificationSamsung Galaxy Watch 9 40mmOnePlus Watch 4
Battery capacity44 mm: 445 mAh; 40 mm: 390 mAh646 mAh typical; 632 mAh rated
Battery lifeUp to 30 hours with AOD onUp to 5 days smart mode; 3 days heavy use; 16 days power saver
ChargingFast wireless charging, WPC-basedCharging base with USB-C cable
Water resistance5 ATM; IP685 ATM; IP69; IP68
Durability / certificationsMIL-STD-810HMIL-STD-810H

Compatibility

Compatibility specifications comparison
SpecificationSamsung Galaxy Watch 9 40mmOnePlus Watch 4
Phone compatibilityAndroid 13.0 or later; more than 1.5 GB RAM; Google Mobile ServicesAndroid 9.0 or later; GMS 23.45.23 or later
Companion appGalaxy Wearable; Samsung HealthOHealth
Colors44 mm: Graphite, Silver; 40 mm: Graphite, CreamMidnight Titanium; Evergreen Titanium

Additional specifications

Additional specifications specifications comparison
SpecificationSamsung Galaxy Watch 9 40mmOnePlus Watch 4
Case materialAluminumTitanium alloy
Peak brightness3,000 nits peak600 nits typical; 1,500 nits high-brightness mode; 3,000 nits peak in supported sports modes
Charging time44 mm: 100% in 90 minutes, 45% in 30 minutes; 40 mm: 100% in 80 minutes, 50% in 30 minutesApproximately 75 minutes
Release statusAvailable. Released 2026, August 07Available. Released 2026, April
Model numbersSM-L340, SM-L350, SM-L345F, SM-L355F, SM-L345U, SM-L355U—
Card slotNoNo
CameraNoNo
3.5 mm headphone jackNoNo
USBNoNo
RadioNoNo
2G bandsGSM 850 / 900 / 1800 / 1900—
3G bandsHSDPA 850 / 900 / 2100—
4G bands1, 2, 3, 4, 5, 7, 8, 12, 13, 14, 18, 19, 20, 25, 26, 28, 34, 38, 39, 40, 41, 66, 71—
Network speedHSPA, LTE—
SAR (US)1.06 W/kg (body)—
SAR (EU)0.70 W/kg (body)—
Additional durability featuresArmor Aluminum 2—
Pixels per inch—310 ppi
Packing list—Watch; charging base; strap; USB-C cable; user guide; safety and warranty booklet
Smart recognition—Running; walking; cycling; swimming; rowing machine; elliptical
Maximum charging power—Approximately 7.5 W
Operating temperature—0–35 °C

Similarities

  • Both have 2 GB RAM.
  • Both have NFC.
  • Both are water resistant to 50 m.
  • Both take calls over Bluetooth.
  • Both have OLED displays.
  • Both offer 32 GB of storage.

In summary

Get the Samsung Galaxy Watch 9 40mm if you want ECG heart-rhythm readings and a lighter watch for all-day wear, or the OnePlus Watch 4 if you would rather have longer battery life and a premium titanium build.

Back to compared products ↑

In-stock alternatives

Amazfit Balance 2For Samsung Galaxy Watch 9 40mmAmazfit Balance 2View product ↗Samsung Galaxy Watch 8 ClassicFor Samsung Galaxy Watch 9 40mmSamsung Galaxy Watch 8 ClassicView product ↗Google Pixel Watch 3For OnePlus Watch 4Google Pixel Watch 3View product ↗WHOOP ONE 5.0 SensorFor OnePlus Watch 4WHOOP ONE 5.0 SensorView product ↗

Related comparisons

Samsung Galaxy Watch 9 40mmSamsung Galaxy Watch 9 44mmSamsung Galaxy Watch UltraSamsung Galaxy Watch 9 40mmGoogle Pixel Watch 3Samsung Galaxy Watch 9 40mmSamsung Galaxy Watch 8 ClassicSamsung Galaxy Watch 9 40mmSamsung Galaxy Watch Ultra 2025Samsung Galaxy Watch 9 40mmSamsung Galaxy Watch 9 40mmAmazfit Balance 2Samsung Galaxy Watch 9 40mmGoogle Pixel Watch 5 41mmSamsung Galaxy Watch 9 40mmHuawei Watch 6 Pro 43 mmSamsung Galaxy Watch 9 40mmGarmin CIRQA Smart Band
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