Preheat oven to 425 degrees.
Tear off four pieces of foil, each about 12 by 15 inches long. Place a tilapia fillet in center of each piece of foil. Spread 1-1/2 tsp. ginger over each fillet. Drizzle each with 1 Tbs. soy sauce and 1/2 tsp. sesame oil. Season with pepper.
Fold top of foil to meet bottom edge. Crimp edges tightly to seal. Arrange packets in a single layer on a large, rimmed baking sheet. Bake until fish is opaque, 10 to 12 minutes. Serve hot.