Question: how long to hike 20 km?
Answer: It takes about two hours to walk 10K at a moderate pace. Half-Marathon: 13.1 miles or 21 kilometers. It can take up to 4 or 4.5 hours to walk a half-marathon without stopping, but some walkers can finish the distance in 3–4 hours. Marathon: 26.2 miles or 42 kilometers.