Using a sharp knife to cut off tops and bottoms of grapefruits so they sit steady on cutting board, then remove peel and pith in strips from top to bottom. Slice grapefruit into disk-shaped pieces and place in a bowl. Split, pit and peel avocado, slice it lengthwise into 8 pieces and add to bowl.
In a small dish, mix together honey, 1 tbsp (15 mL) lime juice and olive oil and pour over fruit. Season with salt and pepper. Garnish with cilantro. Transfer to a serving dish and spoon remaining juices overtop.