We report a case of choroidal melanoma with massive extraocular extensions through the sclera. A 64-year-old woman reported blurred vision in her right eye. At the first visit, visual acuity was 10/20 OD. An ophthalmological examination revealed a raised choroidal mass and exudative retinal detachment in the lower retina. A diagnosis of peripheral choroidal melanoma was confirmed by additional test results. Because the tumor size was large and no systemic metastasis was found, we recommended enucleation. However, the patient refused and requested only to be followed without treatment. Seven months later, the tumor showed extraocular extensions through the sclera into subconjunctival space and she finally agreed to undergo enucleation. Histopathologic findings showed that the tumor was a mixed cell malignant melanoma of the choroid. The eye was filled with tumor cells, and the tumor had massive extraocular extensions into the orbit through the sclera and scleral emissarium vessels. The intraocular tumor was markedly necrotic, which indicated rapid growth. Choroidal melanomas can increase quickly in size resulting in extraocular extensions through the sclera.