Forerunner 255S

Part Number 010-02641-03

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Feature
Specs
In The Box
Update
Accessories
Compatible Devices

RUN AT A HIGHER LEVEL

You’re making strides. Now, let’s take the next step. Get the training and recovery insights you’ll need to notch your best time yet.

Get an overview of your sleep, HRV status and daily workout with morning report.

Charge less, train more with up to 12 days of battery life in smartwatch mode and up to 26 hours in GPS mode.

Push your limits with a built-in triathlon feature and 30+ activity profiles.

Plan your strategy with daily suggested workouts, course details and more on the race widget.

Utilize a full suite of advanced metrics and training tools to reach your goals.

READY FOR THE LONG RUN

Get an uninterrupted picture of your daily health and nightly sleep with up to 12 days of battery life in smartwatch mode and up to 26 hours in GPS mode.

AS LIGHT AS A FEATHER

With its sleek design and 39g weight, you’ll almost forget you’re wearing Forerunner 255S — even when you’re asleep.

SWEAT-READY MATERIALS

Featuring easy-to-use buttons and a silicone band, this watch is ready to wear — and tear — with durable Corning Gorilla Glass 3.

Light on the wrist. Not on features.

MORNING REPORT

Receive an overview of your sleep, recovery and training outlook as soon as you wake up — alongside HRV status and weather. You can even customize your report to show you what you want to see.

HRV STATUS

Gain a deeper understanding of your overall health, recovery and training performance through heart rate variability while you sleep, based on technology developed by our Firstbeat Analytics team.

BUILT-IN SPORTS APPS

Tap into 30+ built-in activities, including the triathlon and open-water swimming profiles — new to the Forerunner 255 series. For races and brick workouts, transition to the next activity with a single button press.

RACE WIDGET

Get ready for your next race with training tips, personalized daily suggested workouts and completion time predictions based on course details, weather and performance.

DAILY SUGGESTED WORKOUTS

View your entire week of daily suggested workouts, which adapt after every run to match your performance and recovery as well as the races coming up in your Garmin Connect smartphone app calendar.

GARMIN COACH

Free adaptive training plans include 5K, 10K and half-marathon programs, featuring guidance from expert coaches that adapt to you and your goals.

WRIST-BASED RUNNING POWER

See how much power you’re applying to the trail or the road so you can manage your effort and fine-tune your training. No accessory required.

RECOVERY TIME

Know how long to recover before your next high-effort workout based on your latest training as well as overall stress, sleep and daily activities outside of workouts.

PACEPRO FEATURE

To help you plan your race day strategy, this feature offers GPS-based pace guidance for a selected course or distance, so you can tailor your efforts to what’s ahead.

GRADE-ADJUSTED PACE

Don’t run out of steam before the activity is over. Understand how to adjust your pace over varying terrain to perform according to your plan.

TRAINING STATUS

Using new indicators such as HRV status, your recent exercise history and performance, get an easy insight into your overall effort — and whether you’re training productively, peaking or strained.

ACUTE LOAD

See your training history, and compare the intensity of your recent workouts to the optimal range to help improve your fitness.

TRAINING EFFECT

See how your workouts influence your endurance, speed and power with aerobic and anaerobic training effect feedback.

PERFORMANCE CONDITION

While you run, get an analysis of your pace and heart rate for a real-time assessment of your current ability to perform.

WRIST-BASED RUNNING DYNAMICS

This smartwatch measures crucial running metrics such as cadence, stride length, ground contact time and more.

COURSES

Create or find existing courses in the Garmin Connect app, so you’ll never run out of places to run. Or plan one on other platforms such as Strava and Komoot, then automatically sync them to your Forerunner.

VISUAL RACE PREDICTOR

Based on your running history and overall fitness level, get an estimate of what your pace could be for a 5K, 10K — or even a marathon. Plus, trend data highlights your training’s impact over time.

CROSS-TRAINING

Mix up your training with different types of workouts. Free HIIT, strength, cardio, yoga and Pilates workouts come preloaded on the watch, and you can download more from the Garmin Connect app.

A depth of wellness insights.

WRIST-BASED HEART RATE

The watch constantly samples your heart rate¹ with our latest-generation heart rate sensor and will alert you if it stays too high or too low while you’re at rest. It also helps gauge how hard you work during activities — even while swimming.

BODY BATTERY ENERGY MONITORING

Track your body’s energy levels so you can find the best times for activity and rest¹.

SLEEP SCORE AND ADVANCED SLEEP MONITORING

Get a score for your sleep’s quality and insights on how you can do better. Even keep track of the different sleep stages as well as heart rate, stress, Pulse Ox² and respiration.

PULSE OX SENSOR

This wrist-based Pulse Ox sensor² monitors blood oxygen saturation levels to support advanced sleep monitoring and altitude acclimation.

WOMEN’S HEALTH TRACKING

Use the Garmin Connect app to track your menstrual cycle or pregnancy. Log symptoms, get exercise and nutrition education, and more. Even see and log details on your wrist with the Women’s Health Tracking app.

INTENSITY MINUTES

Our intensity minutes feature tells you when during the day you earned them and during what activity.

STRESS TRACKING

Find out if you’re having a calm, balanced or stressful day. Relax reminders will even prompt you to do a short breathing activity when the watch detects that you’re feeling stressed.

HEALTH SNAPSHOT FEATURE

Log a 2-minute session to record key stats, including heart rate¹, heart rate variability, Pulse Ox², respiration and stress. Then generate a report with those stats to share via the Garmin Connect app on your compatible smartphone.

Stay connected at every step.

SATIQ TECHNOLOGY AND MULTI-BAND GPS

Get superior positioning accuracy and optimized battery life.

SMART NOTIFICATIONS

Receive emails, texts and alerts right on your watch when paired with your Apple or Android smartphone. You can even respond to texts if you have an Android phone.

SAFETY AND TRACKING FEATURES

If you feel unsafe or if your watch senses that an incident occurred, the Assistance and incident detection features³ send your location to emergency contacts. Incident detection is enabled by default for select activity profiles only.

LIVETRACK FEATURE

Use LiveTrack to let friends and family follow your real-time location³ and even view your entire preplanned course. Rest assured that your loved ones know exactly where you’re running.

GARMIN CONNECT APP

See your health and fitness information, connect and compete with friends, sign up for challenges to earn badges and more — all in one free, zero-subscription app.

CONNECT IQ STORE

Download custom watch faces, add data fields, and get apps and widgets from the Connect IQ Store app downloaded on your compatible smartphone.

Forerunner 255 Series
Dedicated Website

Learn More

How to use your running watch?

Learn More

See your stats, and track your goals in our Garmin Connect online community

Learn More

¹Activity tracking accuracy

²This is not a medical device and is not intended for use in the diagnosis or monitoring of any medical condition; see Garmin.com/ataccuracy. Pulse Ox is not available in all countries.

³When paired with your compatible smartphone. For safety and tracking feature requirements and limitations, see Garmin.com/safety.

Apple is a trademark of Apple Inc., registered in the U.S. and other countries. Android is a trademark of Google LLC.

Bluetooth Headphone Compatibility

General
Lens Material	Corning Gorilla Glass 3
Bezel Material	fiber-reinforced polymer
Quick Release bands	(18 mm, Industry standard)
Strap material	silicone
Physical size	41 x 41 x 12.4 (mm) Fits wrists with a circumference of 110-175 mm
Color display
Display Size	1.1" (27.5mm) Diameter
Display resolution	218 x 218 pixels
Display Type	sunlight-visible, transflective memory-in-pixel (MIP)
Weight	39 g
Battery life	Smartwatch mode: Up to 12 days GPS-only GNSS mode: Up to 26 hours All-Systems GNSS mode: Up to 20 hours All-Systems GNSS mode plus Multi-Band: Up to 13 hours
Water rating	5 ATM
Memory/History	4 GB

Clock Features
Time/date
GPS Time Sync
Automatic daylight saving time
Alarm clock
Timer
Stopwatch
Sunrise/sunset times

Health Monitoring
Wrist-based Heart Rate (constant, every second)
Daily Resting Heart Rate
Abnormal Heart Rate Alerts	(high and low)
Respiration rate (24/7)
Pulse Ox Blood Oxygen Saturation	(spot-check, and optional all-day acclimation and in sleep)
Fitness Age
Body Battery Energy Monitor
All-day Stress
Relaxation breathing timer
Sleep	(advanced)
Sleep score and insights
Hydration	(in Garmin Connect and optional Connect IQ widget)
Women's Health	(in Garmin Connect and optional Connect IQ widget)
Health snapshot

Sensors
GPS
GLONASS
Galileo
Multi-frequency Positioning
SATlQ TECHNOLOGY
Garmin Elevate wrist heart rate monitor
Barometric altimeter
Compass
Gyroscope
Accelerometer
Thermometer
Pulse Ox Blood Oxygen Saturation Monitor

Daily Smart Features
Connectivity	Bluetooth, ANT+
Connect IQ (downloadable watch faces, data fields, widgets and apps)
On-device Connect IQ Store
Smart Notifications
Text response/reject phone call with text (Android only)
Calendar
Weather
Realtime settings sync with Garmin Connect mobile
Battery saver (customizable low power watch)
Controls smartphone music
Find My Phone
Find My Watch
VIRB Remote
Smartphone compatibility	iPhone and Android
Pairs with Garmin Connect Mobile
Garmin Share

Safety and Tracking Features
LiveTrack
Live Event Sharing	Android Only
Incident Detection during select activities
Assistance

Activity Tracking Features
Step counter
Move bar (displays on device after a period of inactivity; walk for a couple of minutes to reset it)
Auto goal (learns your activity level and assigns a daily step goal)
Calories burned
Floors climbed
Distance traveled
Intensity minutes
TrueUp
Move IQ
Garmin Connect Challenges app	(optional Connect IQ app)

Gym & Fitness Equipment
Available gym activity profiles	Strength, HIIT, Cardio and Elliptical Training, Stair Stepping, Floor Climbing, Indoor Rowing, Pilates, Yoga
Strength workouts
HIIT workouts
Yoga workouts
Pilates workouts
On-screen workout animations
On-screen workout muscle maps

Training, Planning and Analysis Features
HR zones
HR alerts
HR calories
% HR max
% HRR
Recovery time
Auto max HR
Morning report
Race glance/widget
HRV status
HR Broadcast (broadcasts HR data over ANT+ to paired devices)
Respiration rate (during exercise)	(with compatible accessory)
GPS speed and distance
Customizable data pages
Customizable activity profiles
Auto Pause
Interval training
Improved interval (includes open repeats, intervals data page, rest screen and auto detection)
Advanced workouts
Downloadable training plans
Auto Lap
Manual lap
Rest timer
Configurable lap alerts
VO2 Max (Run)
VO2 Max (Trail Run)
Training Status	improved
Training Load
Training load focus
Training Effect
Training Effect (anaerobic)
Primary benefit (Training Effect labels)
Improved recovery time
Daily suggested workouts	(7 days)
Custom alerts
Audio prompts
Finish time
Virtual Partner
Race an Activity
Auto multisport activities
Manual multisport activities
Course guidance
Touch and/or button lock
Auto scroll
Activity history on watch
Physio TrueUp

Running Features
Available run profiles	Running, Outdoor Track Running, Treadmill Running, Indoor Track Running, Trail Running, Virtual Running, Ultra Running
GPS-based distance, time and pace
Running dynamics	(with compatible accessory)
Vertical oscillation and ratio	(with compatible accessory)
Ground contact time and balance	(with compatible accessory)
Stride length (real time)	(with compatible accessory)
Cadence (provides real-time number of steps per minute)
Running power	(with compatible accessory)
Performance condition
Lactate threshold	(with compatible accessory)
PacePro Pacing Strategies
Run workouts
Race predictor
Course- and weather-specific race predictor
Foot pod capable

Outdoor Recreation
Available outdoor recreation profiles	Hiking, Skiing, Snowboarding, XC Classic Skiing, Stand Up Paddleboarding, Rowing
Point-to-point navigation
Bread crumb trail in real time
Back to start
TracBack
UltraTrac mode
Up Ahead
Elevation profile
Distance to destination
Barometric trend indicator with Storm Alert
Trail run auto climb
Vertical speed
Total ascent/descent
Future elevation plot
Projected waypoint
Sun and moon information

Cycling Features
Available cycling profiles	Biking, Indoor Biking, Mountain Biking, eBiking, eMountain Biking
Alerts (triggers alarm when you reach goals including time, distance, heart rate or calories)
Courses
Bike lap and lap maximum power (with power sensor)
Race an activity
FTP (Functional Threshold Power)	(with compatible accessory)
Compatible with Vector and Rally (power meters)
Power meter compatible
Compatible with Varia Vision (head-mounted display)
Compatible with Varia radar (rear-facing radar)
Compatible with Varia lights
Speed and cadence sensor support (w/sensor)

Swimming Features
Available swim profiles	Pool Swimming, Open Water Swimming
Open-water swim metrics (distance, pace, stroke count/rate, stroke distance, swim efficiency (SWOLF), calories)
Pool swim metrics (lengths, distance, pace, stroke count, swim efficiency (SWOLF), calories)
Stroke type detection (freestyle, backstroke, breaststroke, butterfly) (pool swim only)
Drill logging (pool swim only)
Basic rest timer (up from 0) (pool swim only)
"Repeat on" rest timer (pool swim only)
Auto rest (pool swim only)
Time and distance alerts
Pacing alerts (pool swim only)
Countdown start (pool swim only)
Pool swim workouts
Critical swim speed
Underwater wrist-based heart rate
Heart rate from external HRM (real-time during rests, interval and session stats during rests, and automatic heart rate download post-swim)	(with HRM-Swim or HRM-Pro)

Kid Activity Tracking Features
Toe-to-Toe Challenges app	(optional Connect IQ Toe-to-Toe Challenges app)

Connectivity
Smart trainer control

Forerunner 255S
Charge/data cable
Documentation

Forerunner 255S

Forerunner 255S

RUN AT A HIGHER LEVEL

READY FOR THE LONG RUN

AS LIGHT AS A FEATHER

SWEAT-READY MATERIALS

Light on the wrist. Not on features.

MORNING REPORT

HRV STATUS

BUILT-IN SPORTS APPS

RACE WIDGET

DAILY SUGGESTED WORKOUTS

GARMIN COACH

WRIST-BASED RUNNING POWER

RECOVERY TIME

PACEPRO FEATURE

GRADE-ADJUSTED PACE

TRAINING STATUS

ACUTE LOAD

TRAINING EFFECT

PERFORMANCE CONDITION

WRIST-BASED RUNNING DYNAMICS

COURSES

VISUAL RACE PREDICTOR

CROSS-TRAINING

A depth of wellness insights.

WRIST-BASED HEART RATE

BODY BATTERY ENERGY MONITORING

SLEEP SCORE AND ADVANCED SLEEP MONITORING

PULSE OX SENSOR

WOMEN’S HEALTH TRACKING

INTENSITY MINUTES

STRESS TRACKING

HEALTH SNAPSHOT FEATURE

Stay connected at every step.

SATIQ TECHNOLOGY AND MULTI-BAND GPS

SMART NOTIFICATIONS

SAFETY AND TRACKING FEATURES

LIVETRACK FEATURE

GARMIN CONNECT APP

CONNECT IQ STORE

Forerunner 255 SeriesDedicated Website

How to use your running watch?

See your stats, and track your goals in our Garmin Connect online community

General

Clock Features

Health Monitoring

Sensors

Daily Smart Features

Safety and Tracking Features

Activity Tracking Features

Gym & Fitness Equipment

Training, Planning and Analysis Features

Running Features

Outdoor Recreation

Cycling Features

Swimming Features

Kid Activity Tracking Features

Connectivity

Forerunner 255 Series
Dedicated Website