Shadine Duquemin emulated her brother Zane to break her own Island Games record in the discus.
Duquemin beat the mark set in the Isle of Wight in 2011 by almost three metres as she threw a distance of 48.58.
Guernsey's Great Britain Under 20 international Cameron Chalmers won his first Island Games gold medal, winning the 400m ahead of Jersey's Sam Dawkins.
Claire Lidster, who came out a six-year retirement to take 100m hurdles silver earlier in the week, took the same coloured medal in the 400m hurdles, finishing a tenth of a second behind Ynys Mon's Mikaela Harrison.
In the 100m Guernsey's Josh Allaway was second behind Cayman Islands' Tyrell Cuffy while Jersey's Philip Williams was third.