Soak 4 large bamboo skewers in water for 30 minutes.
Butterfly the shrimps leaving shell intact. Remove vein. Rinse and pat dry with paper towels.
Place butter, minced garlic, dried thyme, and salt in a small microwave safe dish. Place in the microwave and microwave on 70% power for 45 seconds to melt the butter. Remove from microwave and stir to combine.
Skewer 3 shrimps by the tail on each bamboo skewer. Wrap both exposed ends with aluminum foil to prevent the bamboo skewers from burning. Brush marinade over shrimp flesh.
Place shrimp skewers on preheated grill with cut side down for 3 to 4 minutes or until they turn pink.
Remove and serve immediately.