Cut the sweet potatoes in half lengthwise, then cut them into ¼-inch slices.
In a large skillet, heat the oil over medium heat. Add the sliced sweet potatoes and garlic.
Sprinkle with the thyme and season with salt and pepper. Cook for 1 minute, stirring to coat. Reduce the heat to low, cover, and cook, stirring occasionally, until the potatoes are tender, about 20 minutes.
A few minutes before you’re ready to serve, add the olives and taste to adjust seasonings, if desired. Drizzle with a little additional olive oil, if desired. Serve immediately.