Add apple to a large bowl and toss in lemon juice to keep from browning. Add the pineapple, mandarin oranges, grapes, and coconut and stir to combine. Gently stir in the yogurt to evenly coat all the fruit.
Cover and refrigerate for at least 4 hours before serving to allow the flavors to meld together. Serve chilled. If you notice some liquid gathering, just stir to reincorporate the juices into the fruit!