One fruit that fits your description is a watermelon. Watermelons have green flesh and a red skin.

There aren’t many common fruits with green flesh and red skin. The most likely candidate is a variety of guava called the Caribbean guava. This tropical fruit has a bumpy, light green skin and a vibrant pink or even reddish flesh inside. It has a sweet and tangy flavor, sometimes described as a mix between strawberry and pear. You can eat the skin or just the flesh.

[Picture of a few guavas, some of them cut in quarters and halves]

Here are some common fruits with green flesh and red skin:

• Red delicious apples - These very popular apples have bright red skin and greenish-white flesh.
• Granny Smith apples - Another widely available variety, Granny Smith apples have hard, tart green flesh under their green skin.
• Cherimoya - Also called custard apple, the cherimoya has smooth creamy green flesh inside its scaly reddish-brown skin.
• Pomegranate - The outer skin of a pomegranate is reddish-brown, and it contains many arils (seeds) surrounded by sweet, tangy, green flesh.
• Red grapes - While most grapes have green or purple flesh, some varieties like Flame grapes have flesh that is distinctly green underneath red or pink skin.
• Red plums - Many plum varieties for eating fresh or cooking have red skin covering green flesh, such as Santa Rosa plums.
• Red guava - The common tropical fruit guava comes in varieties with red skin and green or white flesh inside.
• Red kiwifruit - Like the more familiar green kiwifruit, the red variety has a fuzzy brown skin but contains bright green flesh inside.