The 27-year old has called time on her international career following the conclusion of the FIFA 2019 World Cup qualifying campaign.
The Kilkenny-native was an integral part of Colin Bell's squad having played in all but one qualifying game during the campaign and was named WNT Player of the Year in 2016. Duggan will continue to play for Peamount United in the Women's National League where she recently won the League Cup, beating Wexford Youths in the final.
Duggan won 35 caps for her country having made her senior international debut against South Africa at the Cyprus Cup in 2013. She also balanced her international career with her career, working as a Business Performance Analyst with Accenture.
"It's with great sadness and joy that I'm announcing my retirement from international football. I've had a wonderful time playing for my country and I've made some fantastic memories which I'll remember fondly," Duggan said.
"Unfortunately, with the next major championships three years away, I don't feel like I can give 100% for that length of time. With my work-life outside of football, there are a number of other factors which I've got to consider. I've given it everything over the last few years but now it's time to focus on what I hope to achieve outside of football.
"That opens up the opportunity to one of the younger generation coming through who will be able to progress and help Ireland qualify for their first major championships.
"Of course, I'll still continue playing with Peamount United in the Women's National League and I'd like to thank Colin Bell and the staff, as well as former manager Sue Ronan, for giving me the opportunity to represent my country. Also, I'd like to thank all of my former team-mates, I've made some great friends for life and I wish them all the best in the future.
"Finally, I'd like to thank my family and friends for their constant support over the course of my international career. They've travelled and supported me at a number of matches over the years and it has meant everything to me."
Following Karen's announcement, WNT Head Coach Colin Bell was full of praise for Duggan, "Karen has been a fantastic player for me during my time as Head Coach and I'm sad to hear she's retired," Bell said.
"She has played in almost every match I've managed and she has been a crucial part of the performance culture we've tried to bring in.
"Karen's commitment to the national team has been fantastic. Despite the pressures of her day-to-day work-life, Karen strived to improve and help the team succeed. The improvement from her over the course of the campaign was fantastic and she has been a great role model to the other home-based players.
"I'd like to thank her for her performances on the pitch but also her professional nature and character off it. Karen has been fantastic to work with and I wish her the very best for the future.
"With Karen retired, we'll now be looking to the other young players to begin to step up to the required levels of international football."
FAI CEO John Delaney praised Karen Duggan as a role model for other home-based players to follow. "Karen was one of the most outstanding role models in our Women's National Team over the last few years," said Delaney.
"Home-based, she proved to the younger players coming through the elite player pathway that you can play domestic and international football, and set a fantastic example to follow.
"Part of the team which achieved that fantastic 0-0 draw against the Netherlands in November, Karen played a crucial role in Colin Bell's qualifying campaign and we'd like to wish Karen every success in the future."
Chairperson of the Women's Football Committee and FAI Board Member Niamh O'Donoghue praised Karen's commitment to promoting the women's game off the pitch as well. "I'm sad to hear of Karen's decision to retire from international football," O'Donoghue said.
"She has been one of the biggest stars of the Women's National League and Women's National Team over recent years, playing a crucial role both on and off the pitch. Due to her being home-based, Karen has fulfilled many community and sponsorship roles over the years which has gone a long way to helping promote the WNT.
"Having won the WNT Player of the Year in 2016, Karen has been one of the star names of the team and her influence will be missed. I would like to wish her every success in the future and thank her for her fantastic service."