Combine cilantro, parsley, garlic, shallot, lemon zest and juice, and lime zest and juice in a small bowl. Whisk in olive oil slowly until marinade is combined.
Place shrimp in a large zip-top bag and pour in marinade mixture. Seal bag and gently massage onto shrimp. Refrigerate for 1 to 6 hours.
Preheat an outdoor grill for medium-high heat and lightly oil the grate. Slide 5 shrimp onto each skewer.
Grill shrimp kebabs until they are bright pink on the outside and meat is opaque, about 2 minutes per side. Serve hot.