For this Garmin matchup, choose Forerunner 255 for longer battery and dual‑band GPS; pick Forerunner 745 for triathlon depth and a smaller case.
Forerunner 255
Forerunner 745
Best Value Runner
- Longest battery for long weeks
- Dual‑band accuracy in dense cities
- Two sizes (255/255S)
Forerunner 255
Triathlete Streamlined
- Compact 43.8 mm shell
- Music is standard
- Strong tri profiles + transitions
Forerunner 745
Running and tri watches live on your wrist all day, so the choice shapes your training and your daily routine. Garmin’s mid‑range pair covers the same jobs with different strengths. You’ll get the quick verdict here, plus the trade‑offs that nudge most buyers one way or the other.
In A Nutshell
The Forerunner 255 suits runners who want long battery life, dual‑band GPS for tougher urban routes, and a price that still leaves room for a chest strap. It comes in two sizes and a Music variant if you want offline playlists.
The Forerunner 745 fits athletes who want a compact tri watch with music included and deep training tools baked in. It’s an older model with shorter battery life, but it still brings strong swim‑bike‑run chops in a smaller shell.
Side‑By‑Side Specs
ℹ️ Good To Know: “All + Multi‑Band” on the 255 taps two frequency bands to help in tall‑building zones; see Garmin’s satellite settings page for details (multi‑band explained).
Forerunner 255 — What We Like / What We Don’t Like
✅ What We Like
- Long smartwatch stamina (up to 14 days) and strong GPS time for race weeks.
- Dual‑band GNSS helps lock routes in tough city canyons.
- Two sizes (255/255S) make fit easy for slim or larger wrists.
- Music option adds on‑watch playlists if you want phone‑free runs.
- Garmin Pay means tap‑to‑pay at coffee stops.
⚠️ What We Don’t Like
- No full maps on the watch; breadcrumb navigation only.
- Training Readiness isn’t part of this series; you get HRV Status and Morning Report instead.
- Music requires the specific Music model, which costs more than the base unit.
Forerunner 745 — What We Like / What We Don’t Like
✅ What We Like
- Compact case sits low on the wrist yet keeps full tri profiles.
- Music storage is standard — no need to pick a special version.
- Training tools like Training Status, VO₂ Max, and daily workout picks keep you on track.
- Garmin Pay is built in for quick stops.
⚠️ What We Don’t Like
- Shorter battery life in both watch and GPS modes.
- No dual‑band GNSS, so city accuracy can be less steady near glass and steel.
- Older hardware means fewer new features drop in with updates.
Garmin 255 Or 745: Which Fits You Better
Performance & Speed
Both watches feel snappy during workouts and menus. The 255 rides on newer internals that pair well with its dual‑band GNSS mode, which improves route lines in dense areas. The 745 stays smooth during transitions and multisport starts, and it handles open‑water tracking without fuss. If your routes weave between high‑rises, the 255’s multi‑band mode is the safer bet (All + Multi‑Band on the 255).
Display & Build
Both use Garmin’s transflective MIP screens for easy daylight readability. The 255’s panel is larger at 1.3″, which makes pace and lap data easier to read at speed. The 745 trims size and weight, landing at a compact 43.8 mm and ~47 g that many triathletes prefer under a wetsuit cuff. The 255’s 45.6 mm case and ~49 g are still light and balanced on most wrists.
Battery & Charging
This is where the 255 stretches ahead. In smartwatch mode it’s rated up to 14 days, and up to 30 hours of continuous GPS without music. The 745 is rated for up to 7 days in smartwatch mode, and up to 16 hours of GPS. Those figures come from Garmin’s manuals and spec pages and reflect typical lab conditions; real‑world time varies with sensors, backlight, and music use (255 battery life table • 745 battery specs).
Sensors & Accuracy
Both watches deliver wrist HR, pulse ox, altimeter, compass, and gyros. The 255 adds dual‑frequency satellite reception, which can sharpen tracks around tall buildings and under tree cover. Neither watch carries full topographic maps; breadcrumb courses and turn cues are standard. If you pair an HRM‑Pro chest strap, both open extra running dynamics fields and steadier interval HR.
Software & Updates
You get Garmin Coach plans, Morning Report, race widget, Training Status, and suggested workouts on both. The 255 includes HRV Status, a nightly baseline view tied to sleep, while the 745 leans on its existing training load suite. Training Readiness — the score that fuses HRV, sleep, load, and recovery — isn’t part of the 255 line, and it has not been added to the 745 either; plan on using HRV Status and Training Status as your guideposts (HRV Status explainer).
Ports & Connectivity
Both pair with Bluetooth sensors, ANT+ meters, and Wi‑Fi for music sync and firmware. Each handles LiveTrack and incident alerts. You’ll charge with Garmin’s standard 4‑pin cable. Neither adds LTE or a speaker/mic for calls; if you want wrist calls, you’ll need to look elsewhere in the lineup.
Pricing & Packages
The Forerunner 255 launched at $349.99, with the Music variant at $399.99. The Forerunner 745 debuted higher at $499.99. Street prices swing during sales, but those are the official tiers. Music is included on the 745; on the 255 you pick the Music model if you want offline playlists (launch pricing).
Price, Value & Ownership
The money gap narrows during promos, but structure stays the same: the 255 costs less and lasts longer; the 745 bundles music and a tighter fit.
Where Each One Wins
🏆 Dual‑Band GPS — Forerunner 255
🏆 Music Included — Forerunner 745
🏆 Smaller Case — Forerunner 745
🏆 Best New Price — Forerunner 255
Decision Guide
✅ Choose Forerunner 255 If…
- Battery life matters more than anything and you want fewer mid‑week charges.
- Your long runs pass between tall buildings or heavy tree cover and you want steadier tracks.
- You prefer paying less now and adding accessories only if you need them.
✅ Choose Forerunner 745 If…
- You race tri and want a compact case that sits clean under a wetsuit or cycling sleeves.
- On‑watch music is a must and you don’t want to hunt for a special variant.
- You value mature tri features and you can live with shorter battery time.
Ownership Details That Matter
Battery claims come from Garmin’s device manuals and assume moderate settings. On the 255, the battery life table lists up to 30 hours in GPS‑only, and up to 25 hours in All Systems (shorter in multi‑band). The 745’s table lists up to 16 hours of GPS, or 6 hours when playing music. If you stream playlists or run backlight bright, plan for less time (255 battery chart • 745 battery chart).
Both watches carry a 5 ATM rating and pool/open‑water swim profiles. Each holds about 500 songs for offline playback when set up for music. The 255 needs the Music model; the 745 includes it. Garmin Pay works on both after you add a card through the app (255 specs • Garmin Pay steps).
Why Runners And Triathletes Split On These Two
Runners who cover long mileage weeks tend to favor the 255. Less charging means less chance of a dead watch on tempo day, and the dual‑band mode steadies tracks through downtown corridors. If you also ride and swim, the 255 still handles tri days with proper transitions and clean open‑water tracks.
Triathletes who live inside pool schedules, brick sessions, and travel races often reach for the 745 because of its compact feel and music included. It’s easy to pack, light on the wrist, and ready to cue your playlists without paying for a special variant.
Training Metrics: What You Get On Each
Both watches show Training Status, load, and VO₂ Max. The 255 adds HRV Status, a nightly trend that shapes Morning Report and your race widget. Neither model carries Training Readiness as a native score; you’ll still get recovery time, HRV trends, and load guidance to plan sessions (Training Status overview • HRV Status overview).
Comfort, Fit & Everyday Use
The 745’s smaller case can feel invisible on smaller wrists and under sleeves. The 255’s larger display gives pace, lap, and map‑line fields more headroom, which helps during intervals and navigation. Both weigh under 50 g with soft silicone bands, so neither feels heavy on double‑session days.
Navigation & Safety
Neither watch includes full map tiles, but courses, turn prompts, and back‑to‑start do the job for training routes. LiveTrack and incident alerts work when your phone is nearby. For backcountry maps and a flashlight, you’d step up to the higher lines; for city running and tri courses, this pair covers the basics well.
Smart Features
Both send phone notifications, control smartphone music, and sync over Wi‑Fi. The 745’s music storage comes standard. The 255’s Music edition adds Spotify, Amazon Music, or local files once you set up Wi‑Fi and logins. Either way, pair Bluetooth earbuds and you’re set for long workouts without a phone.
Accessory Pairings That Make Sense
Add an HRM‑Pro for steady interval HR and running dynamics, or a foot pod if you spend winters on indoor tracks. Cyclists can pair power meters and receive cycling dynamics. Swimmers get stroke data and drill logging in pool mode. Both watches play well with the same sensor kit, so you won’t rebuy if you swap models later.
Care & Service
Neither unit has a user‑replaceable battery. Keep the charging contacts dry, rinse after saltwater swims, and wipe the optical sensor clean for the best wrist HR. Firmware updates roll in over Wi‑Fi; set your home network once and let the watch pull updates overnight.
Final Pick For Most Runners
Most buyers should start with the Forerunner 255. It lasts longer, it tracks tougher city routes with dual‑band GNSS, and it costs less new. You still get triathlon profiles, Garmin Pay, HRV Status, and an optional Music model for offline playlists. If a compact case and music out of the box outweigh battery needs, the Forerunner 745 remains a tidy pick that’s race‑ready for swim‑bike‑run days.
Sources: Garmin device manuals and official product pages for specs and battery claims; launch pricing from coverage at The Verge. See links above in the “Battery & Charging,” “Ownership Details,” and “Pricing & Packages” sections.