The first movie, i suppose? 5-6 i think. Simba wasnt 1 년 old when he left Pride Rock. And it takes about 5 years for a lion to grow a full mane. (and i read somewhere the lion king producers said so as well) So when he came back, he was about 5 years old. At the end of the movie however, he has a cub with Nala, which means some time must have passed. So i would say... 6 years?