Garmin Forerunner 255: Sports Features, Battery Life and Everyday Use

The Garmin Forerunner 255 is a sports watch with multi-band GNSS, more than 30 sports modes and up to 14 days of battery life in smartwatch mode. Alongside activities such as running, cycling and swimming, it tracks sleep and is designed for all-day wear.

Design and durability

The Forerunner 255 weighs 49 grams, so it may not feel overly heavy on the wrist during a workout or while sleeping. Its display is protected by Corning Gorilla Glass 3, which helps resist scratches and everyday mechanical damage. That does not mean the glass is unbreakable.

A 5 ATM water-resistance rating allows the watch to be used while swimming or in the rain. The weight and battery figures apply to the Forerunner 255; other size variants may differ.

Sports modes and custom settings

The watch offers more than 30 sports modes, including running, cycling, swimming and other outdoor activities. Choosing the appropriate mode helps record data relevant to the sport.

Users can also create custom sports modes and tailor the metrics they track. This puts the information most relevant to an activity and its goals within easy reach during a workout.

Battery life

The Forerunner 255 offers up to 14 days of battery life in standard smartwatch mode and approximately 30 hours with GPS. The first figure is useful for all-day wear and sleep tracking, while the second gives an indication of endurance on a longer run, hike or bike ride.

Actual time between charges depends on the features and settings used. When planning a long activity, it is therefore best not to treat the maximum battery life as a guarantee.

GPS and multi-band GNSS

The watch supports the GPS, GLONASS and Galileo satellite navigation systems. Multi-band GNSS can improve positioning where signals reflect off buildings or are partially blocked by vegetation. In practice, this may mean a more accurate record of a route, distance and pace, for example in a city or forest.

Accuracy still depends on conditions, and multi-band reception does not eliminate every error. Support for satellite positioning also does not, by itself, establish which specific mapping or navigation features the watch offers.

Sleep and incident detection

The Forerunner 255 tracks sleep quality and estimates sleep stages, including REM, light and deep sleep. Sleep Coach provides personalized recommendations that may help users adjust their sleep habits. Sleep-stage data from a consumer device is an estimate, however, not a medical examination or a guarantee of better recovery.

During supported activities, incident detection can send the user's location to emergency contacts. Pairing the watch with a phone alone is not enough: contacts must also be set up and a connection must be available. An alert is not guaranteed to be sent in every situation.

The Forerunner 255 is a practical choice for someone who wants to track several sports and sleep without charging the watch every day. When choosing a model, consider the specific size variant and how the watch will be used, particularly if battery life is a deciding factor.