Watermelon is one of the most refreshing fruits you can enjoy, especially on a hot day. Its sweet flavor and high water content make it a favorite, but it can spoil faster than many people expect. A watermelon that looks perfectly fine on the outside may already be going bad inside. That’s why taking a moment to check it before eating is important—it can help you avoid an unpleasant taste or even foodborne illness.

One of the easiest ways to tell if watermelon has spoiled is by its smell and texture. Fresh watermelon has a light, sweet scent and firm, juicy flesh. If you notice a sour or fermented odor, or if the fruit feels slimy, sticky, or mushy, it’s best to throw it away. These are clear signs that the fruit is breaking down and bacteria may be present.

Visual clues also matter. Healthy watermelon should have bright red or pink flesh. If you see dark spots, brown patches, or faded color, the fruit may be past its prime. Mold—whether white, green, or black—is a definite warning sign. Even a small amount means the entire watermelon should be discarded, since mold can spread beneath the surface.

Taste can confirm what your senses suspect. If the watermelon tastes fizzy, bitter, or just “off,” don’t continue eating it. To keep watermelon fresh longer, store whole fruit at room temperature, but refrigerate it once cut and eat it within a few days.