Sea urchin spine injuries have been reported in the hand and foot, but there are no published cases in the Achilles tendon. We report an unusual case of Achilles tendinopathy secondary to sea urchin spine injury. The patient had Achilles tendon pain that increased over time and was worsened with weightbearing activity. His left ankle plantarflexion was limited by pain. He had received medical care 3 months earlier to remove sea urchin spines after stepping on a long-spined sea urchin. Bedside ultrasound and imaging studies revealed that there were foreign bodies related to sea urchin spines on the surface of the tendon. The patient was given education about proper footwear and activity modification. His symptoms resolved over time, and he avoided surgical intervention.
