Jersey's Kim Ashton won her second individual cycling gold medal after coming first in the women's road race.
Ashton who won team and individual time trial gold on Sunday, beat the Isle of Man's Elizabeth Holden to upgrade the bronze medal she won two years ago.
And Ashton's performance helped Jersey win team road race gold as well, along with teammates Laura Chillingworth and Claire Treharne.
Guernsey's Sophie Dorey and Jo Watts secured the team bronze medal.
Saaremaa's Mikhel Raim sprinted to gold in the men's road race as Jersey claimed the team bronze medal.
"It was amazing," Ashton told BBC Radio Jersey.
"Road racing is my forte, I knew it was going to be tough with the weather and the gruelling course, but this is the one I wanted."
Raim got the better of the Isle of Man's Nathan Draper and Torkil Veyhe, from the Faroe Islands, who took silver and bronze medals respectively.
They were part of a long-lasting five-man breakaway and made their move on a climb on the Tour de Bretagne course.
Jersey's Chris Spence was the best of the Channel Islanders, coming fifth.
Raim's victory for Saaremaa, the largest island in Estonia, was their second gold of the Island Games.