Darwin made his international debut for Australia in June 2001, coming off the bench against the touring Lions in Brisbane. He also played in the 2001 Tri Nations Series later that year, and was capped against Spain, England, France and Wales. He played in the 2002 Tri Nations Series, as well as being capped another four times during the end of year tour. He played 11 times for Australia in 2003, and was included in the 2003 World Cup squad. It was during the Wallabies' World Cup semi-final win against the All Blacks that Darwin sustained a neck injury that forced him to retire from rugby.
Post playing career
After retirement, Darwin made the switch from player to coach, starting at club rugby level with Sydney's Norths where he was appointed head coach in 2005. In 2006, Darwin was involved with the start up of the Super 14 club, the Western Force, as the Forwards Coach until mid-2006. In 2007, Darwin was selected to be a part of the commentary team covering the 2007 Rugby World Cup in France for the Australian television network, Channel 10. Whilst he France, Darwin was also in training for his first Iron Man triathlon, which he completed in Port Macquarie in April 2008. He finished his second Iron Man, again at Port Macquarie, the following year. At the beginning of June 2008, Darwin moved to Tokyo, Japan, where he served as the Forwards Coach for the Japanese Top League Rugby team, the NTT Shining Arcs, a team owned by Japanese telecommunications giant NTT. Darwin was integral to the club's promotion from the 2nd Division Top East competition to Top League at the end of the 09/10 season. At the beginning of 2010, Darwin married a writer/journalist from Melbourne, Australia. Shortly after, Darwin and his wife returned to Australia in order for Darwin to take up the Scrum Coach/Video Analyst position for the Melbourne RebelsSuper Rugby franchise team. Darwin writes regular columns on rugby matters for www.rugbyzone.com and is still in training for various triathlon competitions.
Coaching
2005: Head Coach at Norths, Sydney, Australia 2006: Forwards Coach at Western Force, Perth, Australia 2008–10: Forwards Coach and Video Analyst at NTT Shining Arcs, Tokyo, Japan. 2010–12: Scrum Coach and Video Analyst/Head of IT at Melbourne Rebels, Melbourne Australia. 2012–13: Forwards Coach for Suntory Sungoliath, Tokyo, Japan.