The 'All Schools Programme' was launched last year with the aim of showing rugby union is a game that everybody can play and that it is not just for elite schools - like Eton College where Prince Harry went.
More than 100 secondary schools joined the project in 2012/13, and 100 more have signed up for 2013/14. Overall, the RFU hopes 750 schools will benefit from the scheme.
Speaking at Twickenham, Prince Harry said: "There are so many good things about rugby. You've got to make rugby cool. I bet you can if you get your proper kit and put that up at school, you'll get more kids wanting to play."
Prince Harry is taking a coaching session for youngsters at Twickenham Stadium. Harry, who is patron of the Rugby Football Union All Schools Programme, is meeting schoolchildren to try and increase the number of pupils playing rugby in state schools.