Dragon fruit, with its bright yellow or red skin and its dramatic spikes, can appear exotic and even intimidating. When you look at this relatively unusual fruit in the supermarket, you may find yourself at a loss as to how to tell if it is ripe. The general color of the fruit is not an accurate indication; these fruits do not start off green, progress through yellow and turn red. Instead, even fully mature and perfectly ripe dragon fruits can be yellow. With a quick examination, however, you will be able to determine whether a particular dragon fruit is ripe.
Pick up the dragon fruit in question and squeeze it gently. An underripe dragon fruit will be firm and hard, while a ripe one will be slightly softer. Do not squeeze hard enough to damage the fruit; some gentle pressure should be enough to reveal how hard the dragon fruit is.
Compare the dragon fruit's color to others nearby. A ripe dragon fruit will have a richer, more vivid color. Ripe yellow dragon fruits will have a golden hue, while red ones will be brighter red than their underripe counterparts. It should not have any discolored patches, though its spikes may be a significantly different color than the fruit itself.
Examine the dragon fruit for any mold, wrinkles, bruises or other signs that it is too old or damaged. A perfectly ripe dragon fruit should be consistently full-bodied -- though not extremely firm -- without any overly soft spots, wrinkles or mold.
Open the dragon fruit and look at its flesh. If your dragon fruit is ready to eat, its flesh will be white or pink -- for red or pink dragon fruits -- or simply white -- for yellow dragon fruits. Regardless of the flesh's color, it will be dotted with small black seeds. These are perfectly edible. The flesh should be pulpy to slightly firm at the most; if your dragon fruit's flesh is still hard, it is not yet ready to eat. If it is soft, the dragon fruit has passed its peak, but -- as long as the fruit shows no signs of rot or decay -- it is still edible.