In a medium bowl, whisk together soy sauce, vegetable oil, sherry, ginger root and garlic. Fill a large resealable bag with the mixture. Place swordfish steaks into the bag with mixture, and shake to coat. Place bag in the refrigerator, and allow the steaks to marinate at least 4 hours.
Preheat an outdoor grill for high heat and lightly oil grate.
Grill swordfish steaks 8 to 10 minutes per side, until the swordfish flakes easily and is opaque in the center.