Declan Coyne is a former student at Degrassi Community School, who made his first appearance in Season 9's premiere Just Can't Get Enough. He is a calm, conceited, and a self-described child nomad, having traveled to four different continents with his father who is a diplomat, his mother, and his fraternal twin sister, Fiona Coyne, of whom he is very protective, which sometimes causes family feuds. His swift and sometimes deceiving acts could come off as arrogant. He has graduated from Vanderbilt Prep, and now is a sophomore at Yale, along with Holly J. Sinclair. He was also friends with Jane Vaughn. He was portrayed by Landon Liboiron.
In Just Can't Get Enough, Declan and his twin sister Fiona are seen at Degrassi for their first day at their new school and Chantay introduces them to Peter and Mia. Declan invites them to a party his parents are having and they accept. When Peter and Mia show up to the party, Declan tells Peter to perform one of his songs in front of everyone, knowing that he would embarrass himself. Declan then introduces Peter to his drug-addicted cousin, Victoria. When Mia realizes there's something wrong with Peter she asks Declan if there's drugs going around and Declan tells her that Peter probably got drugs from Victoria, his cousin. Later, in school Declan shows Peter before and after pictures of people who became addicted to meth and Peter swears he'll never do meth again.
Coming in at #15 is Declan Coyne.