Preheat oven to 450 degrees F. Wash and dry potatoes. Slice them in half lengthwise, or into quarters if they are large. Combine sliced potatoes, oil, thyme and rosemary in a large bowl and toss to coat. Place potatoes on a large rimmed baking sheet and spread them out evenly so that they are not crowded. Sprinkle lightly with salt and pepper.
Roast until tender and brown, 35 to 40 minutes, stirring once after 15 minutes and then again after 25 minutes for even cooking. Transfer potatoes to paper towels to drain. Sprinkle with sea salt and serve immediately.