Kacbu lists 9 Smartwatches that stand out for Sport & Outdoors: Apple, Garmin. This is not a ranking; each product is here because its editorial assessment found it strong for this use.
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.
49 mm · up to 42 hours · Yes
47 mm · up to 168 hours · Yes
42.4 mm · up to 240 hours · 5 ATM
47 mm · up to 360 hours · Yes
45 mm · up to 168 hours · 10 ATM
41 mm · up to 72 hours · Yes
45 mm · up to 96 hours · Yes
46 mm · up to 48 hours · 5 ATM
42.2 mm · up to 120 hours · 5 ATM