<p>Tumor metastasis is an important event in cancer progression, representing an enduring and irrevocable hallmark of cancers. The causes of tumor metastasis are complex and diverse. Arising evidence shows that the dysregulation of calcium signaling plays a crucial role in its initiation and progress. Calcium is an essential secondary messenger that regulates signaling pathways associated with tumor metastasis. The transient accumulation of calcium potentially promotes the advancement of tumor metastasis, while calcium-dependent proteins and calcium-related channels also significantly contribute to such malignant process. Thus, compounds specially targeting calcium channels, transporters or pumps may be therapeutic approaches prohibiting tumor metastasis. This review focuses on exploring the roles of calcium ions, calcium-dependent proteins and calcium-related channels in organotropic metastasis of cancer and its clinical applications in the treatment of metastatic cancers.</p>