Underhill captained
England U18 during their successful 2014
FIRA tournament and played nine times during an unbeaten season, including scoring a try on debut in a player of the match performance against
Scotland, captaining the team to a win in the FIRA tournament and a win against
South Africa. On 17 June 2017 he made his international debut starting in the last test of the tour as England defeated
Argentina to win the series 2–0. On 12 August 2019, Underhill was named in Eddie Jones' 31-man squad for the
2019 Rugby World Cup. He was one of the stars of the semi-final victory over
New Zealand, helping England to reach their first World Cup final since
2007. Underhill started in the
2019 Rugby World Cup final in which England were defeated by
South Africa to finish runners up. Underhill was a member of the squad that won the
2020 Six Nations Championship and later that year he started for the England side that defeated
France after extra-time to win the
Autumn Nations Cup. On 4 July 2021, Underhill scored his first try at international level in a game against the nation of his birth the
United States. He was a member of their
2022 tour of Australia and started in the second test victory at
Lang Park as England ultimately won the series 2–1. Underhill was not initially included in the squad for the
2023 Rugby World Cup. However, he was called up after
Jack Willis was injured during the pool stage. Underhill made his only appearance of the tournament in their last fixture starting in the victory over Argentina as England finished third with the Bronze medal. ==Career statistics==