Sheffield Crown Court heard how Aleksandr Ivanov, 26, punched a woman to the floor in York Street in Sheffield city centre on April 12 before he and Kyle Probin, 23, made off with a bag containing £15 worth of shopping.
Probin was jailed for four-and-a-half-years and Ivanov was jailed for five years and four months.
Both defendants, of Beaumont Road North, Sheffield, had pleaded guilty at an earlier hearing.
The victim, who is aged in her thirties, had returned to Sheffield Train station Station just minutes earlier and was making her way through the city when she was struck without warning.
PC Mark Wilkinson of South Yorkshire Police, said: “This was a particularly cowardly attack in which the victim was struck without word or warning, causing her to suffer severe physical and emotional trauma.
“I hope the sentence sounds a clear message to anyone thinking of committing crime on the streets of Sheffield, as it will not be tolerated.”