Henshaw was named in Ireland training squad for the 2013 Six Nations Championship, and played 58 minutes at fullback for the Ireland Wolfhounds in a friendly against England Saxons on 25 January 2013. Henshaw was released from the senior squad in February and made his debut for Ireland Under-20 on 8 February 2013, starting at fullback in the side's 16–15 victory against England.