St Christopher's has a proud tradition on the rugby field. In 2005, the 1st XV won the Sussex Cup whilst in 2011, the Under 11s won Ashdown House's prestigious Sevens Tournament. Alex King, ex-Wasps and England, attended the school in the 1980s and in recent years many pupils have been selected for the Harlequins Elite Development Squad.
Rugby caters for pupils of all abilities and helps to reinforce the school's focus on teamwork and competition. All boys play rugby at the school from Year 4 onwards and most play in matches, beginning with non-contact at Under 8 followed by nine-a-side contact at Under 9, twelve-a-side at Under 11 and the full 15-a-side game at Under 13.