Samantha Baldwin, 40, was last seen with six-year-old Dylan Madge and Louis Madge, nine, in Nottingham city centre last Monday.
Nottinghamshire Police said all three had been found and were with officers.
A spokesman said: "Police have located Samantha Baldwin, 40, Dylan Madge, six, and Louis Madge, nine.
"They are now with officers and are safe. Thank you for your support in this matter."
The force had been appealing for Ms Baldwin to get in touch and said on Tuesday that there had been no direct sightings of the trio since the missing persons inquiry was launched.
Police said the inquiry was focusing on Newark, Nottinghamshire, Lincolnshire and Manchester.
Two women, aged 62 and 36, who were arrested on suspicion of assisting an offender have been released on bail.