Gethin made his Wales debut against Romania in Wrexham in 2003 and has gone on to become Wales' most capped front row forward and fourth overall on the Welsh forwards list behind Martyn Williams, Colin Charvis and Gareth Llewellyn.
Gethin played in all 10 Grand Slam games in 2005 and 2008 and also featured in every game of the 2003 and 2007 World Cups. He was a part of the British & Irish Lions' first all Wales front row, when he packed down with Matthew Rees and Adam Jones against the Springboks.
A versatile prop who can play on either side of the scrum, Gethin became a national hero in Wales when his charge down try against Ireland at the Millennium Stadium in 2005 secured the Grand Slam for Wales for the first time for over 20 years.
Speaking of his decision to move on Jenkins said:
"I won't leave with any bitterness and will give the Blues everything between now and the end of this season, just the same as I have always done."
"But after that, it will be time for me to have a fresh start and a new challenge."
"I definitely will not be with the Blues next season, and I am going to France to play."