Kacbu lists 20 Smartwatches that stand out for Sport & Outdoors: Amazfit, Garmin, Apple +3. Each product is here because its editorial assessment found it strong for this use; the order is the Match score, computed from official specs and verified editorial tags, with the reasons under every card.
For sport and the outdoors what decides is positioning accuracy, water resistance and how long the battery lasts through a long session. Having positioning is not having dual-band positioning; in cities and under trees the difference grows. In water resistance, an atmosphere rating and a dust-and-water rating describe different things; for swimming look at the first, for diving at the maker's separate statement.
Each card carries what sets the product apart. Open the product page for its strengths, weaknesses and alternatives.

48.5 mm · up to 648 hours · 10 ATM

47.4 mm · up to 504 hours · 10 ATM

49.45 mm · up to 336 hours · 20 ATM

47 mm · up to 360 hours · Yes

47 mm · up to 168 hours · Yes

45 mm · up to 168 hours · 10 ATM

47 mm · up to 336 hours · 5 ATM

46 mm · up to 336 hours · 5 ATM

42.4 mm · up to 240 hours · 5 ATM

43.9 mm · up to 240 hours · 5 ATM

49 mm · up to 42 hours · Yes

47.6 mm · up to 120 hours · 5 ATM

47.4 mm · up to 120 hours · Yes

45 mm · up to 96 hours · Yes

48.5 mm · up to 72 hours · 20 ATM

40.5 mm · up to 144 hours · Yes

40.5 mm · up to 144 hours · 50m

41 mm · up to 72 hours · Yes

42.2 mm · up to 120 hours · 5 ATM

46 mm · up to 48 hours · 5 ATM