Herb Watermelon Feta Salad

½ large chilled seedless watermelon, cut into 1-inch cubes

1 small red onion, sliced

1 cup thinly sliced fresh basil leaves

1 cup chopped fresh cilantro

½ cup minced fresh mint leaves

2 limes, juiced

1 (4 ounce) package crumbled feta cheese

3 tablespoons olive oil

2 tablespoons balsamic vinegar, or more to taste

salt and ground black pepper to taste

Gently toss watermelon, onion, basil, cilantro, mint, lime juice, feta cheese, olive oil, balsamic vinegar, salt, and black pepper together in a large bowl.