Sweet cold watermelon, salty feta, bright lime, and soft basil come together in a refreshing salad with a quick honey–lime vinaigrette that soaks in just enough to make every bite pop.
Chill what you can. If you have time, pop the watermelon cubes and feta into the fridge for at least 30 minutes first. Cold fruit holds its shape better and the salad tastes sharper.
Make the dressing. In a small bowl or jar, whisk together the lime juice, lime zest, honey, olive oil, salt, and several grinds of black pepper until it looks slightly creamy and emulsified. Taste; it should be bright, a bit sweet, and salty enough that it almost tastes too seasoned on its own.
Adjust for your watermelon. If your watermelon is very sweet, leave the dressing as is. If it’s a bit bland or underripe, add another 1/2 tbsp honey or a pinch more salt so the dressing can carry more of the flavor.
Layer the watermelon. Add the watermelon cubes to a wide salad bowl or shallow platter. You want some space for the dressing and feta to tuck between pieces instead of piling into a tall mountain.
Dress gently. Whisk the dressing again (it separates quickly), then drizzle about two-thirds of it evenly over the watermelon. Use clean hands or a large spoon to very gently turn the cubes from the bottom, so most pieces get a light coat without breaking down.
Add basil and onion. Scatter the basil ribbons and, if using, red onion over the dressed watermelon. Toss once or twice very lightly, just to distribute.
Fold in feta last. Add the feta on top and very gently fold it through once or twice. Don’t stir like a green salad or you’ll smear cheese everywhere. A little crumbling is fine; you still want some distinct chunks.
Finish with more dressing (if needed). Taste a few pieces of melon and feta together. If it needs more zip, drizzle on a bit more of the remaining dressing. You might not use it all, especially if your melon is very juicy.
Rest briefly, then serve. Let the salad sit for 5–10 minutes at room temperature so the basil and lime open up. After about 30–40 minutes the melon will start releasing more juice and things get soupier, so serve soon after mixing.