Garmin Forerunner 165 vs 170: Which Should You Buy?

Forerunner 165 vs 170 at a Glance: Key Specs Side by Side

Both watches share the same AMOLED display technology and Garmin’s core training ecosystem, which makes the choice genuinely tricky. The table below captures the figures that matter most, drawn from Garmin’s official UK comparison tool as of June 2025.

Prices correct at time of publication (June 2025). Always check Garmin UK, John Lewis or Amazon UK for current availability.

Display and Design

Screen size, resolution and AMOLED quality

Both the Forerunner 165 and the Forerunner 170 use the same 1.2-inch AMOLED panel running at 390 × 390 pixels. In practice, that means vivid colours, sharp text and a display that is perfectly readable in direct sunlight — a meaningful step up from the MIP screens found on older Garmin running watches. Neither watch offers an always-on display by default (enabling it noticeably reduces battery life on both), but the gesture-to-wake response is fast and reliable on each.

If display quality is your deciding factor, there is no meaningful difference here. Garmin has not altered the screen hardware between generations.

Build materials, colours and strap options

The weight gap — 40 g for the 165 versus 41 g for the 170 — is negligible on the wrist. Both use a lightweight polymer case with a metal bezel ring and ship with a silicone strap in the 20 mm quick-release format, so aftermarket strap compatibility is identical.

Where they differ is in the colour palette. The Forerunner 165 launched with a broader range of case and strap colour combinations, including some popular pastel options. The Forerunner 170’s launch colours are more restrained. This is worth checking on the Garmin UK product pages if aesthetics matter to you, as the range can shift with new stock.

Battery Life: Where the Difference Really Lies

Battery life is the most debated aspect of this comparison in online communities, and for good reason — the two watches trade blows depending on how you use them.

Smartwatch mode: 165 vs 170 compared

In standard smartwatch mode, the Forerunner 170 holds an edge: up to 13 days versus up to 11 days for the Forerunner 165. That is roughly a two-day advantage across a typical week of notifications, step counting and sleep tracking. For most runners, neither figure requires a mid-week charge — but the 170 gives you a slightly larger buffer if you travel or forget to plug in.

GPS workout duration: which lasts longer on a run?

The Forerunner 170 pulls further ahead during active GPS workouts, rated at up to 22 hours in GPS-only GNSS mode compared with the 165’s 19 hours. That three-hour gap is largely irrelevant for 5K and 10K runners, but it becomes meaningful for marathon and ultra-distance athletes. A 20-mile training run at a comfortable pace will push the 165 closer to its ceiling than the 170.

Real-world GPS battery drain is always lower than the headline figure — enabling heart rate monitoring, music playback and multi-band satellite signals all shorten the quoted duration. During testing noted by reviewers at Tom’s Guide, both watches came in below their rated GPS figures when all sensors were active, though the 170 consistently held a proportionally longer charge.

Battery Saver mode and practical day-to-day impact

Here is the nuance that most comparisons overlook: the Forerunner 165 is rated for up to 20 days in Battery Saver Smartwatch mode. Garmin has not published an equivalent figure for the Forerunner 170. If you regularly travel without a charger for extended periods and are happy to disable some smartwatch functions in exchange for endurance, the 165 actually outlasts the 170 in this specific scenario.

The practical takeaway: the 170 wins for GPS-heavy training; the 165 wins (or at least matches) when you need maximum low-power longevity between charges.

GPS and Tracking Accuracy

Satellite systems supported

Both watches support multi-GNSS, meaning they can draw on GPS, GLONASS and Galileo satellite networks simultaneously. Neither model currently offers multi-band (dual-frequency) GPS, which is a feature reserved for Garmin’s higher-end lines such as the Forerunner 265 and Fenix series. For road running and well-mapped trails, multi-GNSS single-band is entirely sufficient. You may notice occasional drift in dense urban canyons or thick tree cover, but this applies equally to both watches.

Independent testing by DC Rainmaker has consistently shown that Garmin’s GNSS implementation in this price bracket produces reliable track-to-track accuracy for standard running routes. The Forerunner 170 does not introduce a new chipset that materially changes this picture.

Heart rate sensor performance

Both watches use Garmin’s Elevate wrist-based optical heart rate sensor. The sensor captures continuous HR data and feeds into HRV Status, a metric Garmin uses to track heart rate variability trends over time. In steady-state running, optical HR accuracy is good on both; during high-intensity intervals with rapid pace changes, a chest strap will always outperform wrist-based measurement regardless of the model.

Running dynamics — cadence, stride length and ground contact time — are supported on both watches when paired with a compatible Garmin accessory such as the Running Dynamics Pod or HRM-Pro Plus. Neither watch measures running dynamics natively from the wrist.

Training and Health Features

Training status, load and readiness

The Forerunner 170 and 165 are closely matched on training intelligence. Both offer Training Readiness (a daily score combining sleep, HRV, recovery time and training load), Daily Suggested Workouts, and Training Status indicators that tell you whether you are peaking, maintaining or showing signs of overreaching.

Garmin Coach structured training plans — covering 5K, 10K and half-marathon distances — are available on both models via Garmin Connect. There is no meaningful functional difference here between the two generations.

Health monitoring: sleep, HRV and Body Battery

Both watches track sleep automatically each night, providing sleep stages, sleep score and an overnight HRV Status reading. Body Battery, Garmin’s energy reserve metric calculated from HRV, stress and activity, is present on both.

These health features are among the most compelling reasons to choose either watch over a basic GPS tracker. The consistency of the data inside Garmin Connect is a genuine differentiator from some competitor platforms, and it applies equally to the 165 and 170.

Music storage and Garmin Pay

This is where the variant labelling matters. Music storage is not included on the standard Forerunner 165 or the standard Forerunner 170 — you need the Music variant of each. The Forerunner 165 Music costs around £269, while the Forerunner 170 Music is approximately £349. Both Music variants support offline Spotify, Amazon Music and Deezer downloads, as well as personal MP3 transfers.

Garmin Pay contactless payment is available on both the standard and Music versions of each model, provided your bank supports the feature.

Price and Value: Is the Forerunner 170 Worth the Upgrade?

Current UK prices for both models

As of June 2025, UK retail pricing is approximately:

• Forerunner 165 — £229 (standard), £269 (Music)
• Forerunner 170 — £299 (standard), £349 (Music)

The Forerunner 170 carries a £70 premium over the standard 165. At this price point, that gap is not trivial — it represents a 30% increase for what is, in core functionality, a closely matched product.

Who should stick with the Forerunner 165?

The Forerunner 165 remains excellent value for money if you run predominantly shorter distances (up to half-marathon), charge your watch at least twice a week, and do not need more than 19 hours of continuous GPS time. It also has the Battery Saver mode advantage for extended trips away from a charger.

If you are coming from a basic GPS watch or a fitness band and want a capable AMOLED running watch with Garmin’s full training ecosystem, the 165 delivers everything you need without the premium of the 170.

Who should upgrade to the Forerunner 170?

The Forerunner 170 makes more sense if you regularly run marathons or ultras (where 22 hours of GPS time matters), want a slightly larger battery buffer in daily smartwatch use, or simply prefer buying the latest generation. It is also worth considering if you anticipate Garmin rolling out software features to the 170 first as the product matures — though at this stage, the feature parity between the two is high.

If you already own a Forerunner 165 and it is working well, the upgrade from 165 to 170 is difficult to justify on features alone. The GPS workout battery improvement is real but incremental.

Verdict: Forerunner 165 or 170 — Our Recommendation

For beginners and intermediate runners covering distances up to half-marathon, the Forerunner 165 is the stronger recommendation. It delivers the same AMOLED display, the same Garmin training ecosystem including Body Battery, HRV Status and Daily Suggested Workouts, and genuinely excellent GPS tracking — all for £70 less. The Battery Saver Smartwatch mode (up to 20 days) is a practical advantage that the 170 does not clearly match.

For marathon runners, ultra-distance athletes, or anyone who wants the absolute maximum GPS workout battery life in this sub-£300 bracket, the Forerunner 170 is worth the premium. Its 22-hour GPS rating gives meaningful headroom for long efforts, and the 13-day smartwatch mode adds a small but welcome buffer.

Both watches sit comfortably within the Garmin ecosystem, syncing seamlessly with Garmin Connect and compatible with the same accessories and third-party app integrations. Neither is a wrong choice — the decision comes down honestly to how far you run and how much you want to spend.

This article is based on official Garmin UK specifications and independent reviews available as of June 2025. Prices were verified against Garmin UK, John Lewis and Amazon UK at the time of writing. Always confirm current pricing before purchasing.

Frequently Asked Questions

What is the main difference between the Forerunner 165 and 170?

The primary differences are battery life and price. The Forerunner 170 offers up to 13 days in smartwatch mode and 22 hours in GPS-only mode, compared with 11 days and 19 hours for the Forerunner 165. The 165 counters with a 20-day Battery Saver Smartwatch mode and a lower UK price of around £229. Core training and health features — including AMOLED display, Body Battery, Training Readiness and HRV Status — are shared across both models.

How long does the Garmin Forerunner 165 battery last?

According to Garmin’s official specifications, the Forerunner 165 lasts up to 11 days in standard smartwatch mode, up to 20 days in Battery Saver Smartwatch mode, and up to 19 hours in GPS-only GNSS mode. Real-world duration will be lower when features such as always-on display, music playback or continuous heart rate monitoring are active.

Which Garmin Forerunner offers the best value for money?

For the majority of runners, the Forerunner 165 offers the best value for money in the UK. At around £229, it provides the same AMOLED screen, the same Garmin training features and nearly equivalent GPS accuracy as the Forerunner 170, which costs approximately £299. The 170’s advantages — longer GPS workout battery and two extra days in smartwatch mode — are most relevant to marathon and ultra runners who need maximum GPS endurance.

Why is my Garmin Forerunner 165 battery draining so quickly?

Several settings can significantly increase battery drain on the Forerunner 165. The most common causes are: always-on display mode (which can halve effective smartwatch battery life), using multi-GNSS with a high GPS update rate during workouts, enabling continuous pulse oximetry, and running music directly through Bluetooth headphones. Check that your GPS settings are appropriate for your activity type, ensure your watch firmware is up to date via Garmin Connect, and consider switching to a lower-frequency HR check in daily use if battery life is a priority.