Antrim surged clear in the second half to win by 17 points.
Offaly's All-Ireland Senior Camogie Championship campaign got off to a poor start with a heavy defeat to Antrim on Saturday.
After leading by three points at half-time, Antrim surged in the second half to run out 4-18 to 1-10 winners in Birr.
Offaly host All-Ireland champions Galway this Saturday.
In the Intermediate Championship, Laois were beaten by Galway in their first group stage match on Saturday, by 0-20 to 0-12 in Ballinasloe.
Laois travel to Kerry this weekend, while Westmeath will start their championship campaign against Dublin.