The Islanders took the first game comfortably, beating Chatham 6-2 behind the pitching of Jordan Stevenson.
Alex Person took the loss on the mound for the Ironmen.
The Islanders narrowly missed the doubleheader sweep, falling to Chatham 3-2 in extra innings.
Ronnie Dickson picked up the win for Chatham while Brody MacDonald was tagged with the loss.
Charlottetown now sits last in the NSBL with a 3-10 record while Chatham is 9-6.