What will the Greek national emblems look like on the F-35A Block 4:
Low-visibility markings:
The nationd al emblems (e.g. the blue anwhite of the Hellenic Air Force) will be gray or charcoal, not blue and white like on other fighters, to harmonize with the stealth paint.
Placement:
A low-visibility Greek national emblem on the vertical stabilizer.
A smaller one on the bottom of the fuselage or near the fuselage under the wings.
Possible “HAF” (Hellenic Air Force) logo with insignia in a font compatible with stealth specifications.
Example from other countries:
Italy, Israel, Norway use similar “low-vis” markings with gray variations of their national insignia.
The Israeli F-35I Adir has insignia that is almost invisible from a distance, for maximum concealment.
Inspiration for the Greek style:
Lockheed Martin has released digital renderings of Greek F-35s with a gray cross instead of the classic blue-and-white national emblem. You can see it here:
https://www.f35.com/f35/global-enterprise/greece.html