Former champions Upper Hill are in Group G where they take on Dandora Secondary and Lenana School in hunt for a place in the round of 16.
Upper Hill coach Gilbert Walusimbi said that he is building a team for the future.
"My boys are under no pressure because we are focused on the future. We have had challenges over the years and right now we just want to rebuild and think of winning titles in future," Walusimbi said.
Upper Hill, who lost their regional title to Dagoretti High in 2018, have been unable to recapture it. They have remained in the cold for years following the exit of former principal now Kibra MP Peter Orero.
Stiff competition is also expected in Group C which has 2022 East Africa silver medallists Highway Secondaryl who play Brownhill and Jehovah Jire in their first and second match at Moi Forces Academy.
Highway, who are coached by Harambee Starlets and Kenya Police Bullets tactician Beldine Odemba, are eying a return to the national games. Last year they lost 1-0 to Dagoretti in the final to relinquish the regional title.
In Group E, hosts Jamhuri High School will entertain Kenya Muslim and Hospital Hill while St Patrick's, Nairobi School and Our Lady of Fatima (OLF) will battle in Group B.
Moi Forces will host Olympic High School and Shammah in Group D, Pumwani Boys will bank on home advantage when they take on Riwa High School and Beth Mugo High School. Githurai Secondary, Genesis Joy and Waylight Secondary complete the boys line up in Group H.
In the girls' contest, defending champions Dagoretti Mixed tackle Embakasi Girls and Pangani Girls in Group A. Former national champions Maina Wanjigi will take on Starehe Girls and Beth Mugo High in Group E.
With school principals believed to play a huge role in the success of school teams, all eyes will be on Dagoretti Mixed who will be playing for the first after the departure of their principal Maurice Okumu, who was transferred to Upper Hill.
In netball, champions St Dorcas Education Centre will leave nothing to chance as they seek to defend their title. They play Langata Barracks and Huruma Mixed in Group A.
They will face stiff competition from Raila Educational Centre, Parklands Arya, Baba Dogo Secondary School, among others.
In basketball 3X3, Dagoretti High and Olympic High will be looking to defend their boys' and girls' titles respectively.
Dagoretti are in Group A together with Aquinas, Nairobi School, Mathari Mixed, Muhuru Muchiri and Kibera Secondary.
Olympic begin their quest in Group A which also has St George's, Peter Kibukosya, Maina Wanjigi, Clay City and St. Claire Nembu.
Rugby 7s will be played from Friday.