1) Place the potatoes in a medium or large saucepan and add enough water to cover by about 5cm. Set the pan over a high heat and bring the water to a boil. Cook for 8 minutes, or until the potatoes are fork tender.
2) Drain and transfer the potatoes to a large bowl. While the potatoes are still warm, add the olives, tomatoes, onion, olive oil, vinegar and thyme and toss to combine. Season, to taste, with salt and black pepper.