Arthroscopic treatment for femoroacetabular impingement syndrome (FAIS) has previously been reported to have favorable short-term results in high-level athletes. Less is known about long-term outcomes. To report outcomes 10 years after hip arthroscopy for FAIS in high-level athletes using validated patient-reported outcome measures (PROMs). Case series; Level of evidence, 4. Patients who underwent hip arthroscopy between November 2011 and January 2013 were included in a local hip arthroscopy registry and completed preoperative PROMs. At 10-year follow-up, the same PROMs were completed. Inclusion criteria were age <40 years at time of surgery, no prior hip surgeries, and a pre-symptomatic Hip Sports Activity Scale (HSAS) level of 7 or 8. The exclusion criterion was total hip arthroplasty at follow-up. The PROMs included the international Hip Outcome Tool-12 items (iHOT-12), the Copenhagen Hip and Groin Outcome Score (HAGOS), visual analog scale (VAS) for overall hip function, European Quality of Life-5 Dimensions questionnaire (EQ-5D) and European Quality of Life-visual analog scale (EQ-VAS), HSAS, and a single question on patient satisfaction. The rates of patients achieving minimal important change and reporting Patient Acceptable Symptom State (PASS) were reported for HAGOS and iHOT-12. For iHOT-12, preoperative results were compared with 1, 5, and 10-year follow-ups. A total of 45 patients (34 men, 11 women; 70 hips; mean age 24.4 years at time of surgery) were included, with 77 patients eligible for inclusion. Significant improvements (P < .001) were seen at 10-year follow-up in all HAGOS subscales: Symptoms, Pain, Daily Activity, Sports, Physical Activity, Quality of Life (50.3 vs 78.6, 59.2 vs 86.8, 65.9 vs 88.8, 37.1 vs 81.1, 24.4 vs 81.1, 32.1 vs 79.3), iHOT-12 (40.1 vs 81.6), EQ-5D (0.59 vs 0.89), EQ-VAS (65.6 vs 80.4), and VAS for overall hip function (48 vs 79). For iHOT-12, the largest change was seen between preoperative and 1-year follow-up values, with consistent results over time. There was no statistically significant difference between HSAS levels preoperatively and at 10-year follow-up (HSAS level 4), with 24% of patients reporting a HSAS level 7 or 8 at the follow-up. Of the patients, 93% reported satisfaction with the surgery. PASS was achieved in 82% for iHOT-12, with a range of 76% to 91% for HAGOS subscales. Furthermore, 93% exceeded the minimal important change for iHOT-12, and a range of 67% to 84% for HAGOS. In a high-level athletic population, significant improvements in long-term outcomes are reported after hip arthroscopy for FAIS, with patients reporting a high satisfaction rate. The results also show that the largest improvement occurs within the first postoperative year, with results being maintained for 10 years.