Ireland Under-20's have won the
Grand Slam four times and the Six Nations Championship five times:
2007(as the Under-21s) ,
2010,
2019,
2022 and
2023. In the pandemic-truncated competition in 2020, Ireland won the
Triple Crown. At the time the competition was halted, Ireland were undefeated and led the table. However, this was not considered a championship nor a grand slam. Ireland won two consecutive Grand Slams in the
2022 and
2023 Six Nations championships, the only nation ever to do so at that point, but were denied a third consecutive Grand Slam and championship title following a final day draw away to England. Despite Ireland and England having both recorded four wins and a draw, England were crowned champions as they had earned one more try bonus point than Ireland. Ireland Under-20's streak of fourteen consecutive Under 20-Six Nations victories (before the England match) and fifteen matches undefeated in the tournament over three seasons (after the match) are tournament records as of 2026; both streaks came to an end with defeat to England 3-19 in the first game of the
2024 tournament. ==Players==