Cook the rotini pasta according to package instructions until al dente. Drain and rinse under cold water to cool.

In a large mixing bowl, combine the cooled pasta, cherry tomatoes, cucumber, red bell pepper, black olives, mozzarella balls, and red onion.

Drizzle the Italian dressing over the salad and sprinkle with dried oregano, salt, and pepper. Toss gently to combine all ingredients evenly.

Cover the salad with plastic wrap and refrigerate for at least 30 minutes to allow the flavors to meld.

Before serving, taste and adjust seasoning if necessary. Garnish with fresh basil leaves if desired.