Four women were celebrating on the River Dart, Devon, on Saturday when the vessel became stuck in mud as the tide went out.
An RNLI spokesperson said the party were were travelling to Dartmouth when they got into difficulty.
The spokesman said the group were "cold but otherwise unhurt".
Posting on the Dart RNLI Lifeboat Facebook page the crew said: "They came back to the lifeboat station for a warm drink and to meet and thank the lifeboat crew.
"The girls were on a hen party and the irony is that the bride to be had requested a 'no-fuss and low-key day'.
"The hens who had arranged the day thought an afternoon afloat on the beautiful River Dart would set the mood for dinner in Dartmouth in the evening.
"Best laid plans and all of that. I don't think they will ever forget the hen party."
A bride-to-be who wanted a "no-fuss and low-key" hen party had to be rescued by the RNLI after their hire boat ran aground in a river.