To start South Bound on the PCT has issues that North Bound trekkers never need concern themselves with. One such is just starting at the border and touching the Northern Terminus. Because it is in the backcountry of the United States it is a minimum of 30 miles to hike to it.
It is illegal to cross the border from Canada into the United States on the trail.
So SoBo hikers have to trek north to the border and then turn around and start south on the trail, literally back tracking over thirty miles.
This year is even more fun due to mother nature. Because of a landslide the one road that is used to reach the trail head near Hart’s Pass is closed indefinitely. Meaning that any SoBo’s have to start at Rainy Pass, another 30 miles further from the Border and back track that 60 miles to start truly going SoBo on the PCT.