Chill the watermelon in the refrigerator for about an hour. Slice into bite-sized cubes and pat dry with a paper towel.

Rinse strawberries, remove stems, and slice into quarters. Peel and dice cucumber. Set aside in a large bowl.

In the large bowl, gently add cubed watermelon, sliced strawberries, diced cucumber, and crumbled feta cheese. Toss lightly to combine.

In a small bowl, whisk together fresh lemon juice, olive oil, salt, and pepper to create the vinaigrette. Adjust seasoning to taste.

Drizzle the vinaigrette over the salad mixture and toss lightly to coat the ingredients without breaking them down.

Add chopped mint just before serving and toss gently. Serve immediately, optionally garnished with additional feta.