Background and objectives: Social distancing and quarantine implanted during the COVID-19 outbreak could have delayed the accession of oncologic patients to hospitals and treatments. This study analysed the management of sarcoma patients during this period in five Spanish hospitals. Design and methods: Clinical data from adult sarcoma patients, soft tissue and bone sarcomas, managed during the COVID-19 outbreak, from 15 March to 14 September 2020 (Covid cohort), were retrospectively collected and time for diagnosis, surgery and active treatments were compared with sarcoma patients managed during the same pre-pandemic period in 2018 (Control cohort). Results: A total of 126 and 182 new sarcoma patients were enrolled in the Covid and Control cohorts, respectively, who were mainly diagnosed as soft tissue sarcomas (81.0% and 80.8%) and at localized stage (80.2% and 79.1%). A diagnostic delay was observed in the Covid cohort with a median time for the diagnosis of 102.5 days (range 6–355) versus 83 days (range 5–328) in the Control cohort ( p = 0.034). Moreover, a delay in surgery was observed in cases with localized disease from the Covid cohort with a median time of 96.0 days (range 11–265) versus 54.5 days (range 2–331) in the Control cohort ( p = 0.034). However, a lower delay for neoadjuvant radiotherapy was observed in the Covid cohort with a median time from the diagnosis to the neoadjuvant radiotherapy of 47 days (range 27–105) versus 91 days (range 27–294) in the Control cohort ( p = 0.039). No significant differences for adjuvant radiotherapy, neoadjuvant/adjuvant chemotherapy and neoadjuvant/adjuvant palliative chemotherapy were observed between both cohorts. Neither progression-free survival (PFS) nor overall survival (OS) was significantly different. Conclusion: Delays in diagnosis and surgery were retrospectively observed in sarcoma patients during the COVID-19 outbreak in Spain, while the time for neoadjuvant radiotherapy was reduced. However, no impact on the PFS and OS was observed.