Diego Equihua-Torres, 23, allegedly stalked two students as they walked from their school into downtown South San Francisco between May 22 and May 25, according to police.
Equihua-Torres never threatened or spoke to the students, but made it obvious he was following them, police said.
Then at about 2:30 p.m. Wednesday, one of the girls called police when she noticed Equihua-Torres following her again.
He was found near Grand and Maple avenues and arrested on suspicion of stalking and annoying/harassing someone under 18 years old, police said.