In the Box Forerunner 255S Music Charge/data cable Documentation Physical & Performance Display Size 1.1" (27.5mm) Diameter Display Type sunlight-visible, transflective memory-in-pixel (MIP) Battery life Smartwatch mode: Up to 12 daysGPS-only GNSS mode: Up to 26 hoursAll-Systems GNSS mode with music: Up to 5.5 hoursAll-Systems GNSS mode: Up to 20 hoursAll-Systems GNSS mode plus Multi-Band: Up to 13 hoursSee Details Display resolution 218 x 218 pixels GPS Yes Weight 39 g Maps & Navigation Memory/History 4 GB READY FOR THE LONG RUN Get an uninterrupted picture of your daily health and nightly sleep with up to 14 days of battery life in smartwatch mode and up to 30 hours in GPS mode. (ALMOST) AS LIGHT AS A FEATHER With its sleek design and 1.7 oz weight, you’ll almost forget you’re wearing Forerunner 255 — 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. 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. RUNNING POWER When using a Running Dynamics Pod or HRM-Pro™ monitor, get a continuous measurement on your wrist of how much power you’re applying to the road as you run, so you can manage your effort. 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. 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. RUNNING DYNAMICS When using a Running Dynamics Pod or HRM-Pro monitor, the Forerunner 255 watch measures crucial running metrics such as cadence, stride length, ground contact time and balance, and more — while comparing to others in the Garmin Connect app. 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. WRIST-BASED HEART RATE The watch constantly samples your heart rate2 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 rest2. IMPROVED SLEEP MONITORING AND SLEEP SCORE Understand how your body is recovering — and get ready for training — with our improved sleep monitoring feature. After waking up, you’ll receive a sleep score, as well as breakdown of your sleep stages, Pulse Ox3 and respiration, alongside detailed insights for improved sleep quality. 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 rate2, heart rate variability, Pulse Ox3, respiration and stress. Then generate a report with those stats to share via the Garmin Connect app on your compatible smartphone. MULTI-BAND GNSS SUPPORT Access multiple global navigation satellite systems, and get access to multiple frequencies sent by navigation satellites for improved accuracy in areas where GNSS signals are reflected, weak or typically don't penetrate — giving you superior accuracy for how far and how fast you’ve run — even in challenging environments. GARMIN PAY CONTACTLESS PAYMENTS Breeze through checkout lines with Garmin Pay contactless payments1 through participating providers. 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 features4 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 location4 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.
