C
| Cadan |
| Cadel |
| Caden |
| Cadhan |
| Cadyn |
| Caedan |
| Caedaoin |
| Caeden |
| Cael |
| Caelam |
| Caelan |
| Caellum |
| Caelum |
| Caetano |
| Cahal |
| Cahan |
| Cahir |
| Cai |
| Caidan |
| Caiden |
| Caidin |
| Caidyn |
| Cailam |
| Cailean |
| Cailon |
| Cailum |
| Cain |
| Caine |
| Cairo |
| Caius |
| Cal |
| Calden |
| Caleb |
| Calen |
| Callan |
| Callen |
| Callum |
| Calub |
| Calum |
| Calvin |
| Calvin-jacob |
| Cameron |
| Cameryn |
| Campbell |
| Camron |
| Canice |
| Caodhan |
| Caoimhin |
| Caolain |
| Caolam |
| Caolan |
| Caolin |
| Caolon |
| Caomhan |
| Carl |
| Carlo |
| Carlos |
| Carraig |
| Carson |
| Carson-james |
| Carter |
| Casey |
| Cash |
| Cason |
| Caspar |
| Casper |
| Cassius |
| Cathain |
| Cathair |
| Cathal |
| Cathan |
| Cathaoir |
| Cavan |
| Cayden |
| Ceadan |
| Cealan |
| Cein |
| Chad |
| Chailym |
| Charles |
| Charley |
| Charli |
| Charlie |
| Chase |
| Che |
| Chea |
| Chen |
| Cheng |
| Chester |
| Chris |
| Christian |
| Christie |
| Christofer |
| Christopher |
| Chun |
| Cian |
| Cianan |
| Ciaran |
| Ciarnan |
| Ciaron |
| Cilian |
| Cillian |
| Cillin |
| Clarke |
| Cobh |
| Cobi |
| Coby |
| Coby-jack |
| Codey |
| Codie |
| Cody |
| Cody-jack |
| Cody-james |
| Cody-junior |
| Cody-lee |
| Coen |
| Cohan |
| Cohann |
| Cohen |
| Coirbin |
| Colby-james |
| Cole |
| Coleton |
| Coletyn |
| Colin |
| Colm |
| Coltan |
| Colten |
| Colton |
| Colton-carl |
| Colum |
| Columba |
| Comghall |
| Comhan |
| Conaire |
| Conal |
| Conall |
| Conan |
| Conchuir |
| Conchur |
| Conghaile |
| Conin |
| Conlaed |
| Conlaith |
| Conlan |
| Conlaodh |
| Conleith |
| Conleth |
| Conlin |
| Conlon |
| Conn |
| Connaire |
| Connall |
| Connel |
| Conner |
| Connlan |
| Connlaodh |
| Connlaoth |
| Connleth |
| Connlith |
| Connolly |
| Connor |
| Conor |
| Conrad |
| Cooper |
| Coran |
| Corban |
| Corey |
| Corey-james |
| Corey-paul |
| Corin |
| Cormac |
| Cormaic |
| Cory |
| Craig |
| Cristian |
| Cruz |
| Cu |
| Cuan |
| Cuinn |
| Cullen |
| Curtis |