Remove the stems and leaves from the radishes and discard or save for another use. Trim off the ends of the radishes. Cut the radishes in half lengthwise.
Add the radishes to a bowl with the oil, add salt, garlic, oregano. Mix well with clean hands.
Cook the radishes in a 400F (200C) air fryer for 10 to 12 minutes, or until nice and crispy.