The Forerunner 265 is a running watch built around an AMOLED touchscreen with an optional always-on mode. The bezel is fiber-reinforced polymer, the lens is Corning Gorilla Glass 3 and the watch is rated to 5 ATM, which covers swimming and showering but not diving or high-pressure water sports.
Two case sizes share the model. The 46 mm watch is the Forerunner 265: 46.1 x 46.1 x 12.9 mm, 47 g, a 1.3 in (32.5 mm) display at 416 x 416 pixels, 22 mm industry-standard quick release bands, and up to 13 days of smartwatch battery. The 42 mm watch is Garmin's Forerunner 265S: 41.7 x 41.7 x 12.9 mm, 39 g, a 1.1 in (28.1 mm) display at 360 x 360 pixels, 18 mm quick release bands, and up to 15 days of smartwatch battery. Both fit different wrists — 135 mm to 205 mm on the 46 mm case, 115 mm to 178 mm on the 42 mm case.
Positioning uses multi-band GNSS with SatIQ, which selects the satellite mode to balance accuracy against battery drain. In GPS-only mode the 46 mm runs up to 20 hours and the 42 mm up to 24 hours; with all systems and multi-band enabled those figures are 14 and 15 hours. Both hold 8 GB of music.
Training data includes training readiness, an improved training status, sleep score and insights, and Pulse Ox blood oxygen with spot checks plus optional all-day acclimation and overnight readings. Garmin Pay handles contactless payment. Swim tracking covers pool metrics — lengths, distance, pace, stroke count, SWOLF and calories — and open-water sessions.
Compatibility: industry-standard quick release bands, 22 mm on the 46 mm case and 18 mm on the 42 mm case. Charging uses the Garmin proprietary plug charger.
