Spice-Rubbed Foil-Packet Fish with Watermelon Salsa

Spice-rubbed fish is bright, zesty, and full of flavor; the cool, refreshing watermelon salsa is the perfect complement. This dish cooks easily in foil—on the grill, over a campfire, or in the oven—producing tender, flaky fish with minimal cleanup.

Foil Packet Fish with Watermelon Salsa

Grilling fish in foil packets is my go-to method in warm weather, especially for delicate fillets that might fall apart directly on the grates. The sealed packet traps steam and essentially poaches the fish, leaving it moist and flaky without drying out. Foil packets are also practical: you can assemble them in advance, refrigerate, and grill or bake when ready—cleanup is easy, making this a great recipe for weeknights, outdoor meals, and camping.

Ingredients For The Fish

Begin with four boneless, skinless fillets (about 6 ounces each). Squeeze lime over the fillets, then rub with a simple spice blend for maximum flavor. The mix below uses smoked paprika, kosher salt, onion powder, garlic powder, cayenne, ground oregano, and black pepper. If you prefer mild heat, reduce the cayenne by half or omit it entirely.

Watermelon Salsa

The watermelon salsa provides a cool, slightly sweet contrast to the spiced fish. It’s made with diced seedless watermelon, red onion, jalapeño, cilantro, lime juice, and a touch of olive oil. Making the salsa ahead allows the flavors to meld and keeps the meal fresh and vibrant when served.

How To Make A Foil Packet

• Tear off an 18″ x 12″ sheet of heavy-duty foil for each fillet.
• Place the seasoned fish in the center of each sheet.
• Bring the long sides of the foil up so they meet above the fish.
• Fold the ends twice to create a seal, leaving enough room inside for steam to circulate.
• Fold the short ends to close the packet completely.
• Grill or bake as directed in the instructions below.

Ingredients

Watermelon Salsa:

• 2 cups diced seedless watermelon, about 1/4″ pieces
• 1/4 small red onion, finely diced
• 2 tablespoons roughly chopped fresh cilantro
• Juice of 1 lime
• 1/2 jalapeño, seeded and finely diced (adjust for heat)
• 1 tablespoon olive oil

Fish and Seasoning:

• 4 boneless, skinless fish fillets, 6 oz each (striped bass, salmon, cod, or halibut)
• 1 teaspoon smoked paprika
• 1 teaspoon kosher salt
• 1/2 teaspoon onion powder
• 1/2 teaspoon garlic powder
• 1/2 teaspoon ground cayenne pepper (use 1/4 teaspoon to reduce heat)
• 1/4 teaspoon ground oregano
• 1/8 teaspoon black pepper
• Juice of 1/2 lime
• 4 teaspoons olive oil (for drizzling)
• 4 pieces heavy-duty aluminum foil, 12 x 18 inches
• Lime wedges for serving

Instructions

1. Combine the watermelon salsa ingredients in a bowl: diced watermelon, red onion, cilantro, lime juice, jalapeño, and olive oil. Stir gently and refrigerate for at least 20 minutes so the flavors meld.
2. In a small bowl, mix the smoked paprika, salt, onion powder, garlic powder, cayenne, oregano, and black pepper. Pat the fish fillets dry, squeeze lime juice over them, and rub the spice blend evenly onto each fillet.
3. Lay out four large sheets of heavy-duty foil (approximately 18″ x 12″). Place one fillet in the center of each sheet and drizzle with about 1 teaspoon of olive oil per fillet.
4. Fold the short ends of the foil together and double-fold to seal. Fold in the long sides to seal the packet, leaving a little space inside so steam can circulate during cooking.
5. Cook the packets according to your method of choice (see options below). After cooking, let the packets rest for 5 minutes before carefully opening to avoid hot steam.
6. Top each fillet with a generous spoonful of watermelon salsa and serve with lime wedges.

Grill or Campfire Method

Preheat a grill to medium-high or set a cooking grate over your campfire. Place the foil packets on the grill or grate and cook until the fish is just cooked through, about 10–12 minutes depending on thickness. Remove, rest 5 minutes, then open and top with salsa.

Oven Method

Preheat the oven to 450°F (230°C). Arrange the foil packets on a baking sheet and bake until the fish is just cooked through, about 12–15 minutes. Let packets rest 5 minutes, then open carefully and top with salsa.

Recipe Notes & Tips

• Swap fish types freely: this method works well with salmon, cod, halibut, striped bass, or similar fillets.
• Adjust heat: reduce or omit cayenne and jalapeño to suit sensitive palates.
• Prep ahead: assemble packets and salsa up to a day in advance; keep refrigerated until ready to cook.
• Serving suggestion: enjoy with a simple green salad, grilled vegetables, or a side of rice to soak up the juices.

Yield, Time, and Nutrition (approximate)

Yield: 4 servings. Prep: about 15 minutes. Cook: about 15 minutes. Total time: roughly 30 minutes. Estimated per serving: ~314 calories, 39.5 g protein, 13 g fat, 8 g carbohydrates.

More Foil Packet Ideas

• Grilled clams in foil
• Shrimp scampi foil packets
• Cajun shrimp in foil
• Easy grilled fish fillets in foil
• Sausage, butternut, and Brussels foil packets

If you try this foil packet fish with watermelon salsa, consider making the salsa a little ahead of time for the best flavor. The contrast of warm, spiced fish and cool, fruity salsa is refreshing and especially enjoyable on a sunny day.