The duo, who compete for Havant, have been selected to represent England at the Japan Karate Association European Junior Championships in Serbia on May 21 and 22.
Alfie, 16, is a second dan black belt and attends Mayfield School.
He will be going to his third European Championships and his continued progress will stand him in good stead on the big stage when he steps up into a tough age group.
His first European competition was in Prague and he then went to Germany where he got a bronze medal in the team kumite (sparring) event.
Havant coach Steve Fife said: ‘Alfie is in a strong category this year, 16 to 18-years-old in kata (patterns) and kumite.
‘He has grown tall now and is working on his fitness and building up strength as well.
‘Hopefully he can better the bronze medal he secured in Germany last year.’
For William, nine, this is his first European tournament.
He is a first dan black belt and has been been out to the World Championships in Japan to watch his brother taking part.
That will have given him valuable insight into what to expect.
His progress has been superb and he is a popular member of the England squad, along with his brother.
They are two of the top karate talents in the country and both travel to London to train with the national squad.
Fife added: ‘William is training with the national squad twice each month and it is going well.
‘He has watched Alfie at the World Championships in Japan, to experience the atmosphere at top-level karate.
‘I’m sure William will put in a good performance in the kata and kumite events.
‘And I hope he can bring home a European medal at the age of nine – that would be absolutely fantastic.
‘To have one in the England team from Havant karate dojo is great but two, and both brothers, is superb.’
The Cunninghams will also have the full support of their family, as well as their friends and training partners in the national squad as they go for medals.
Fife added: ‘Their parents Lisa and Geoff are over the moon and will be there in Serbia to watch them compete.’
Havant train in the theatre at Havant Academy, Wakefords Way, PO9 5JD.
They are a friendly club practising traditional Japanese shotokan karate and welcome new members, beginners and those with experience.
See the club website havant-jka.co.uk/ for more information about how to join.