The 10 year old, from Telford, has been invited by the Team GB coach to compete in the Seguira Cup next year.
Due to the expense of the trip Billy and his family have had to raise funds for the journey and his school and fellow pupils have now got in on the act.
The youngster was joined by his mother Heidi and Tom Currie, from Billy’s club, Shropshire Wado Ryu.
They were at Aqueduct Primary School, Telford, where they showed off their skills and led karate sessions with the pupils. The youngsters all dressed in sports gear and were asked to bring £1 towards the event.
Billy’s mother said afterwards they had managed to raise more than £300 towards the much-anticipated trip.