Garmin Forerunner 170 vs Forerunner 265: Which Should You Buy?

Overview

The Forerunner 265 is a proven mid-range training watch with verified real-world performance data, multi-band GPS, and a full suite of athlete-focused metrics at $449. The Forerunner 170 is a newer, cheaper entry at $299.99 that promises similar physiological tracking on an AMOLED display, but lacks any verified real-world performance data at the time of writing. This comparison is partly asymmetric: one device has been tested extensively, the other has not.

Specs at a glance

Price: Forerunner 170 at $299.99 vs Forerunner 265 at $449
Display: Both AMOLED color touchscreen
GPS: Forerunner 265 confirmed multi-band GNSS (GPS, GLONASS, Galileo, dual-frequency); Forerunner 170 GPS chipset unconfirmed
Battery (GPS mode): Forerunner 265 confirmed at ~13h multi-band, ~20h standard GPS; Forerunner 170 battery life unconfirmed
Battery (smartwatch): Forerunner 265 ~13 days; Forerunner 170 unconfirmed
Weight: Forerunner 265 at 47g (265S: 39g); Forerunner 170 unconfirmed
Sensors: Both include wrist optical PPG heart rate, SpO2, barometric altimeter, skin temperature, HRV tracking
Water resistance: Forerunner 265 confirmed 5 ATM; Forerunner 170 unconfirmed

GPS and tracking accuracy

The Forerunner 265 delivers confirmed multi-band GNSS performance. In real-world testing it holds accuracy in urban canyons and dense forest, performing on par with the COROS Pace 3 in track and trail conditions. Garmin's post-processing applies more aggressive data smoothing than some rivals, which is a stylistic choice rather than a deficiency, but worth knowing if you want raw trace fidelity.

The Forerunner 170's GPS chipset has not been confirmed. Whether it includes multi-band or relies on standard GNSS is unknown. No real-world accuracy figures exist yet. Buyers who prioritize GPS precision in challenging terrain cannot currently verify what they are getting with the 170.

On wrist optical heart rate, the Forerunner 265 has been compared against ECG reference data. Resting heart rate accuracy is solid. HRV data from the 265's PPG sensor has been judged unsuitable for research or clinical use, and should be treated as a general trend indicator rather than a precise metric. The same caveat almost certainly applies to the Forerunner 170, which uses a comparable PPG-based HRV implementation.

Battery life

The Forerunner 265 delivers approximately 13 hours in multi-band GPS mode and around 20 hours in standard GPS mode. Smartwatch mode lasts roughly 13 days. That 13-hour multi-band ceiling is a real constraint for ultramarathon runners and long-course triathletes. For half marathons, marathons, and standard triathlon distances it is more than sufficient.

The Forerunner 170's battery life is unconfirmed. At its lower price point and positioning below the 265, it would be reasonable to expect shorter GPS runtime, but no verified figures are available. Purchasing decisions that hinge on battery life cannot be made confidently for the 170 right now.

For athletes: who wins?

Road running: Forerunner 265. Confirmed GPS accuracy, training load metrics, and real-world validation make it the safer pick. The 170 may match it once tested, but that is speculation.
Trail running: Forerunner 265. Multi-band GPS is confirmed and performs well in dense canopy. The 170's GPS capability in these conditions is unknown.
Triathlon and multisport: Forerunner 265. Multisport modes are proven and the 265 has a track record with triathletes. The 170's multisport feature set has not been independently verified.
Recovery and health tracking: Tie on paper. Both carry the same physiological sensor stack on paper. In practice, the 265's resting HR accuracy has been validated against ECG reference data. The 170 has not been tested yet. Treat HRV data from either device as a directional guide, not a clinical measure.

Verdict

Buy the Forerunner 265 if you want a proven training watch with verified GPS accuracy, known battery life, and a tested sensor suite. It costs $150 more than the 170, but you know exactly what you are getting. The Forerunner 170 may be a strong value option once real-world testing arrives, and the $150 saving is not trivial, but purchasing it today means accepting unconfirmed GPS performance, unknown battery life, and no independent accuracy validation. For serious runners and triathletes, that uncertainty is too costly. Wait for hands-on reviews of the 170 before committing, or spend the extra $150 and buy the 265 with confidence.