Apple Watch SE 3 Overview & Key Description

The SE 3 is Apples refreshed entry-level smartwatch for 2025. It brings in several features that were previously reserved for the premium lines, while still aiming for a more accessible price point. The idea is to get many of the modern essentials (health, fitness, connectivity) in a lighter / simpler package.

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Key Features & Specs

Here are its main features and specifications:

Category Details

Cases / Colors / Sizes Aluminum case. Available in two finishes: Midnight and Starlight.
Two sizes: 40 mm and 44 mm.
Display Always-On Retina display using OLED LTPO.
Peak brightness: up to ~1,000 nits.
Covers Ion-X front glass with improved durability: 4 more crack-resistance vs previous generation.
Processor / Storage Uses the S10 chip (64-bit dual-core, plus 4-core Neural Engine).
Storage: 64 GB.
Sensors & Health / Wellness Second-generation optical heart sensor (heart rate, high/low & irregular rhythm notifications).
Temperature sensor (used for e.g. retrospective ovulation estimates etc.).
Compass, always-on altimeter, high-g accelerometer, HDR gyroscope, ambient light sensor.
Sleep app with sleep stages, Sleep Score, sleep apnea notifications.
Cycle Tracking with retrospective ovulation estimate.
Connectivity / Network GPS only version + GPS + Cellular version.
Supports 5G cellular on cellular models.
WiFi (802.11n), Bluetooth 5.3.
Controls & Gestures Digital Crown with haptic feedback, Side button.
New gestures: double-tap (thumb + index finger) and wrist-flick to dismiss alerts / snooze / answer calls etc.
Audio / Speaker / Media Speaker and microphone.
For the first time (in SE line), support for playing media (music / podcasts) directly through the speaker.
Battery Life & Charging All-day battery life of up to 18 hours under normal usage.
In Low Power Mode: up to ~32 hours.
Fast-charging: 15 minutes charging gives ~8 hours of normal use. Up to ~80% in ~45 minutes.
Also short charge (~8 min) gives ~8 hours of sleep tracking.
Durability & Water Resistance Water resistance to 50 meters (suitable for swimming etc.).
Other Safety / Features Fall detection, Emergency SOS, Crash Detection etc.
On-device Siri, with more local processing.

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Things Not Included / Limits Compared to Premium Models

SE 3 does not have an ECG sensor.

It does not have a blood-oxygen (SpO) sensor.

The display is not as rugged or bright in every scenario as Ultra etc., though the improvements are significant.

Some advanced health sensors in Series/Ultra models are missing.