Step 1: Trim any silver skin or excess fat from the pork tenderloins. Pat them dry with paper towels.
Step 2: In a medium bowl, combine the chopped rosemary, thyme, oregano, minced garlic, sea salt, black pepper, and olive oil. Mix well to form a paste.
Step 3: Place the pork tenderloins in a large resealable bag or shallow dish. Pour the herb marinade over the tenderloins, ensuring they are fully coated. Massage the marinade into the meat.
Step 4: Refrigerate for at least 2 hours, or up to 6 hours for best flavor. Do not marinate longer than 12 hours.
Step 5: Preheat your grill to medium-high heat (400-450°F / 200-230°C). Clean the grates thoroughly.
Step 6: Remove the tenderloins from the marinade, letting any excess drip off. Place them on the hot grill grates.
Step 7: Grill for 2-3 minutes per side to get a good sear and grill marks, rotating frequently.
Step 8: Reduce the heat to medium-low, or move the tenderloins to a cooler part of the grill. Continue to cook, turning occasionally, for another 15-20 minutes, or until an instant-read thermometer inserted into the thickest part reads 140-145°F (60-63°C).
Step 9: Transfer the cooked tenderloins to a cutting board, tent loosely with aluminum foil, and let rest for 5-10 minutes. This allows the juices to redistribute.
Step 10: Slice the pork tenderloin into 1/2 to 1-inch thick medallions and serve immediately. Enjoy your perfectly grilled pork tenderloin!