Pluto's orbital period is 248 Earth years. This means it takes Pluto 248 Earth years to complete one full orbit around the sun.

To figure out when Pluto last went around the sun, we need to know when its last perihelion (closest point to the sun) occurred. Pluto's last perihelion was in September 1989.

Therefore, Pluto last completed a full orbit around the sun in September 1989.