The honest short answer is "not that much." You definitely could use your Apple Watch or a similar product as a hiking smartwatch if you just download the right third-party apps. Of course, you'd definitely be missing out on a few key traits. For example, standard smartwatches are not water-resistant. They aren't nearly as durable as the hiking watches on our list, and their batteries certainly can't last for days or weeks on end like some of our watches can. Theoretically, you could find a typical smartwatch that meets these criteria, and you'd have a reliable hiking or diving smartwatch on your hands. Of course, the simplest option is just to look for the smartwatches geared towards hiking, which are sure to have the durable design, incredible battery life, and water-resistant frame that you need while on the trail.