Mix watermelon, diced cucumber, jalapeño pepper, garlic, yellow bell pepper, green onion, mint, lime juice, olive oil and salt in a large bowl.
Take 1/2 of the mixture and add to a blender and pulse until desired smoothness.
Add to the bowl with the other 1/2 of the watermelon mixture and combine well.
You can serve at room temperature or chilled.
Note: I like to add a few cucumber slices to the gazpacho for garnish if serving individual and add a rosemary twig.
Make ahead tip! You can make this 1 day in advance. Just keep refrigerated in a sealed container!