Garmin Forerunner 165 vs 265

The row that is missing from one of these tables

Garmin publishes a battery table per watch, broken down by satellite mode. Lay the Forerunner 165 and Forerunner 265 tables next to each other and the interesting thing is not a number, it is an absence: the 265 has a row called All + Multi-Band GPSand the 165 does not. The 165's best row is All Systems GPS. There is no multi-band figure for it because there is no multi-band mode in it.

That matters more than the screen, the price or the strap, because multi-band reception is the specific hardware that addresses the complaint most people have about a cheap running watch: a track that drifts through buildings, bridges and tree cover. No firmware update adds a frequency band the receiver cannot hear.

Garmin's own figures, mode by mode

Now read the two best-accuracy rows against each other, because this is the part every other comparison of these watches gets backwards. In its most accurate mode the 165 states 17 hours. In its most accurate mode the 265 states 14. The cheaper watch lasts longer in its best mode — because its best mode is the weaker one. That is not a win, and anyone quoting 17 against 14 as a battery advantage is comparing two different specifications.

The same trap appears in our own derived arithmetic, so we will say it out loud: per manufacturer-stated GPS hour in each watch's best mode, the 165 works out at $11.76 and the 265 at $31.36. Those two figures are not like-for-like, because the modes behind them are not. They are published together anyway, because hiding the unit is how a spec sheet misleads without lying. The live gap between the two watches today is $239.

What has actually been measured on these watches

This is where the pair separates in a way no amount of price-cutting changes.

The Forerunner 265 has a peer-reviewed measurement.In a 2025 Frontiers in Physiology study of 100 recreational runners, the 265 and 265S were tested against a treadmill graded exercise test with fingertip blood lactate. The watch returned a usable threshold result 65.2% of the time across 23 participants — the best completion rate of the three watches in the study — while overestimating threshold pace by roughly a quarter. Note what that protocol required: the Garmin arm of the study used an ECG chest strap, not the wrist sensor. So the completion figure is a vote of confidence in Garmin's algorithm, not in its optical hardware.

The Forerunner 165 has nothing. No independent validation of this model exists that we could find, which is the normal state of affairs in this category and the reason it scores 5 out of 10 on evidence rather than higher.

The Forerunner 55 has the worst measurement on this site. It is one of the very few watches ever tested in a peer-reviewed heart-rate study, and in the 2025 placement study it recorded a bias of approximately 33 bpm during burpees — the largest error in that paper. Being measured at all is unusual; being measured and coming last is why it cannot rank above the other two here. We would rather publish that than quietly leave the watch off the page.

Which one to buy

Buy the 265 if any of these is true: your usual route has buildings, canyons or heavy tree cover; you want the most accurate positioning Garmin sells at this price; you want the longer-lasting smaller case, because the 265S actually states better figures than the 46 mm in every mode (15 days, 24 h GPS-Only, 15 h multi-band). The full record is in our 265 review.

Buy the 165if your running is on roads and trails with open sky, and the money matters. It is a genuinely good watch with Garmin's full training platform, an AMOLED screen and an 11-day stated battery; what it lacks is the one receiver mode that fixes GPS drift, and if you do not have GPS drift you are paying for nothing. Our 165 review has the detail.

Buy neitherif endurance is what you came for. At the money these two occupy, a COROS PACE 4 states 41 GPS hours in All-Systems mode against the 265's 20 GPS-Only hours, with dual-frequency positioning included — the trade is COROS's unvalidated optical sensor and a smaller app ecosystem. We put that case properly in Forerunner 570 vs COROS PACE 4 and rank the whole field in best running watches on a budget.

What neither watch fixes

Both use a wrist optical sensor, and no current-generation Garmin optical sensor has been independently validated. If your reason for upgrading is that heart rate reads 150 while you are warming up, the multi-band receiver will not help, the AMOLED screen will not help, and the extra 4 GB of music storage will not help. The measured answer to that problem is a strap or an armband — the evidence is in wrist vs chest strap accuracy, and the cheap fix is in better heart rate accuracy.

Three checks that settle it

• Look at your last ten GPS tracks. If the line is clean, multi-band buys you nothing and the 165 is the better value. If it cuts corners through buildings, that is exactly the failure multi-band addresses.
• Decide whether you want the smaller case. Garmin states better battery figures for the 42 mm 265S than for the 46 mm in every single mode, which is unusual and worth knowing before you default to the bigger watch.
• Check whether you need music on the watch. The 165 publishes 4 GB and a 6.5-hour all-systems-with-music figure; the 265 publishes 8 GB. The 55 has neither, and that is the real reason it is a different class of watch rather than a cheaper one.