Thaw shrimp, if frozen. Preheat oven to 425 degrees F. Line a large shallow roasting pan with foil; set aside. Peel and devein shrimp, leaving tails intact if desired. Rinse shrimp; pat dry with paper towels.
In the prepared roasting pan combine shrimp, Swiss chard, dried cranberries, garlic, salt, and pepper. Drizzle with oil; toss gently to coat.
Roast, uncovered, for 8 minutes. Stir; roast, uncovered, for 3 to 5 minutes more or until shrimp are opaque. If desired, serve with lemon wedges.