James Rael has been with Munster Academy for the last year, playing club rugby with Garryowen after playing his schools rugby with Castletroy College.
The Limerick-born hooker featured in last summer's IRB Junior World Championship in South Africa where the Ireland Under-20s claimed their best ever finish of 5th place. The 6ft 1in forward secured the bonus point for his side against Italy, scoring a try in the second half.
The 21-year-old has nine caps with the Ireland Under-20 side, having also competed in last year's U-20 Six Nations campaign. His performances in the number two jersey earned him a place in the Munster Academy in 2012.
Commenting on the westerners' latest signing, Connacht assistant coach Dan McFarland said: "We are delighted that James will be joining us next season. He is coming from an environment that has produced a string of talented hookers.
"James is a talented ball player with a solid set piece game. Connacht will provide the opportunities and support for him to drive on to the next level."