Osteosarcoma (OS) is a malignant tumor originating from the mesenchymal tissue. Simultaneous reports of lung and bone metastases (BM) in OS are rare in the literature. A total of 353 new cases of lung metastases (LM), 93 new cases of BM, and 59 new cases of LM and BM were diagnosed in the Surveillance, Epidemiology and End Results (SEER) database from 2010 to 2019. Univariate and multivariate logistic regression analyses were used to identify risk factors for LM and/or BM, and Cox regression analyses were performed to identify the prognostic factors for LM and/or BM. Kaplan–Meier (K–M) curves and log-rank tests were used to analyze the overall survival of patients with LM and/or BM. LM was diagnosed in 353 patients. Female sex, tumor size >100 mm, telangiectatic OS type, central OS type, N1 stage, other locations, BM, surgical treatments, radiotherapy and chemotherapy were significantly correlated with LM. 93 patients were diagnosed with BM. 25 to 59 years old, T1 stage, presence of LM, liver metastases, radiotherapy, and surgical treatments were significantly correlated with the BM. 59 patients were diagnosed with LM and BM. The chondroblastic OS type, small cell OS type, T1 stage, N1 stage, other locations, liver metastases, radiotherapy, and surgical treatments were significantly correlated with LM and BM. Metastases, radiotherapy, and surgery at the primary site were significantly associated with LM and/or BM. Chemotherapy at the primary site has been shown to be effective in improving the survival rate of LM and/or BM. Of the OS patients with LM, 61.47% died, and older age, BM, no surgery, and no chemotherapy were harmful to survival. 72.04% of OS patients with BM died, and N1 stage, no surgery, and no chemotherapy were harmful for survival. 69.49% of OS patients with LM and BM died, and older age and no chemotherapy were harmful for survival.