Background: There is limited evidence on the safety of return to sexual activity after hip arthroscopy. Aim: To determine the positional safety of sexual activity after hip arthroscopy relative to hip instability and/or impingement risk. Study Design: This study is an observational study. Methods: 12 common sexual positions were identified based on previous research. Gender-specific hip motion was then assessed for the possibility of postarthroscopic hip instability (due to disruption of iliofemoral ligament [interportal capsulotomy] repair) and/or impingement (labral or capsular compressive stress with disrupted repair) for all 12 positions (both right and left hips; 15 unique male and 14 unique female positions). Instability risk was defined as greater than 0 degrees hip extension, greater than 30 degrees external rotation (ER), or greater than 30 degrees abduction. Impingement risk was defined as greater than 90 degrees hip flexion, greater than 10 degrees internal rotation, and greater than 10 degrees adduction. Outcomes: A majority of both male and female sexual positions caused either instability or impingement, with only 4 positions in women and 4 positions in men deemed "safe" by avoiding excessive hip motion. Results: Return to sexual activity after hip arthroscopy may cause instability in 10/15 of male positions and 5/14 female positions. Most male positions (6/10) were at risk for instability because of excessive ER. 2 positions were unstable because of a combination of ER and extension, one was due to extension, and one abduction. In female instability positions, all 5 were unstable because of excessive abduction. Impingement may be observed in 5 of 15 male positions and 6 of 14 female positions. In male impingement positions, all were due to excessive adduction. 4 female positions risked impingement due to excessive flexion and 2 positions due to internal rotation. Clinical Implications: This study demonstrates risks that should be considered when counseling patients preoperatively and postoperatively regarding sexual activity. Strengths & Limitations: This study closely models a hip preservation patient population by using 2 young and otherwise healthy individuals. The most significant limitation of this investigation was its basis with only 2 young healthy volunteers (one male, one female) in a single motion capture session using surface-based spherical retroreflective markers from a previous investigation. Conclusion: After hip arthroscopy, patients need to be made aware of the possibility of hip instability (10 of 15 men; 5 of 14 women) and impingement (5 of 15 men; 6 of 14 women) due to excessive hip motion that may compromise their outcome. Copyright (C) 2020, International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.