Police said the children and Marie Williams, 25, appear to be fine and are on their way back to Long Beach.
According to authorities, Williams has a mild mental retardation and has a maturity level of an 8-year-old. She is neighbors with Nicholas Sanders, 6, at an apartment complex near Santa Fe Avenue and Spring Street. Sarah White, 8, was just visiting a friend at the apartment complex.
Williams took the children to get something to eat but did not return home on Saturday. Police said they were last spotted getting off a train at Willow Street and Long Beach Boulevard in Long Beach.
Then on Monday morning, a man spotted the trio at a Metro station in Sylmar and called police. Officers responded to the location and verified that it was the missing children and woman.
It remains unclear where the children and Williams were during the time they were missing, or how they ended up in Sylmar.