A 13-year-old boy presented with 3 days of left-sided periorbital pain, swelling, mucoid discharge, and fever to 103°F, with onset 1 day after swimming in the ocean. Within 12 hours, he experienced rapid clinical deterioration with formation of a superomedial subperiosteal abscess and an epidural abscess with leptomeningitis despite treatment with broad-spectrum intravenous antibiotics. The patient underwent urgent left orbitotomy with abscess drainage and functional endoscopic sinus surgery. Intraoperative cultures grew Shewanella algae and Escherichia coli . The patient showed marked clinical improvement following surgical intervention and tailored antibiotic therapy. This is the first reported case of orbital abscess with acute bacterial rhinosinusitis due to infection with Shewanella algae .