Bring a large pot of salted water to a rapid boil. Add the rotini pasta and cook until al dente, about 8-10 minutes. Drain and rinse under cold water.

In a mixing bowl, combine halved cherry tomatoes, diced cucumber, finely diced red onion, sliced black olives, and mozzarella balls. Toss gently to mix.

Once cooled, fold the pasta into the vegetable mixture until evenly combined.

Whisk together olive oil, red wine vinegar, Italian seasoning, salt, and pepper in a separate bowl until smooth.

Pour the dressing over the pasta and vegetable mixture, gently toss to combine without breaking the mozzarella.

Cover and refrigerate for at least 30 minutes before serving.