Thru-hiking, when an individual hikes the entire distance of an extended trail, is a growing pastime for adventure enthusiasts. Resilience, mental toughness, and motivation are facilitators for completion of ultra-endurance activities; however, there is little research on these constructs in thru-hikers. The current study examined experiences of 128 thru-hikers on the Appalachian Trail (AT) to understand the resilience, mental toughness, and motivation necessary to complete their thru-hike. Results indicated differences in mental toughness between those who completed the AT and those who did not (t(124) = 2.038, p < 0.05); no differences in resilience or motivation were found. Additionally, open-ended responses suggested that social support facilitated success. Future research should track hikers during the thru-hiking experience to better understand the influence of social support on resilience, motivation, and mental toughness. This information may be helpful for recreation specialists and land managers as they tailor public facilities to better support thru-hiking.