About 75 cm long. Thin tail. Camping site near Grado, Italy, northern Adriatic sea. It climbed a tree in the rough bark and i followed it to take these photos.
It looks like a whip snake, either a Balkan whip snake or a green whip snake. They are both present in the very north of Italy, close to Slovenia. They both vary in color, but the coloration of this one seems to be more similar to the Balkan whip snake.
See also this discussion.