Tie tenderloin at 2-inch intervals with kitchen string.
Combine oil and garlic in a bowl; brush over meat. Mix basil, rosemary, sea salt, and black pepper together in a bowl; sprinkle evenly over the meat.
Roast beef tenderloin in preheated oven until beginning to firm and is hot and slightly pink in the center, 40 to 50 minutes. An instant-read thermometer inserted into the center should read 140 degrees F (60 degrees C).