Teams from Zambia, Uganda, Tanzania, Rwanda and Burundi will compete at the National Age Group Swimming Championship on June 22-23 at the Kasarani Aquatic Arena.
Hosts Kenya are expected to field over 40 teams.
Aquatics Kenya Executive member Heize Kahindo said the teams will arrive by Friday.
"It's encouraging to have the swimmers from the region grace the championships. This will make it competitive and I believe our swimmers will rise to the occasion," observed Kahindo.
The championships is a qualifier for the Africa Aquatics Zone 3 Swimming Championships in Burundi in November and the World Long Course Championship in Hungary in December.
The championships received a Sh300,000 boost from ORS, a leading brand under A&Z Nutraceuticals Ltd.
Kenya Aquatics President Maureen Owiti said: "We are immensely grateful for ORS's support. This sponsorship will enhance the quality and organisation of the championships, providing our young athletes with the motivation and resources they need to excel."
Enid Kanyiri, Managing Director of A&Z Nutraceuticals Ltd added: "We are delighted to partner with Kenya Aquatics in the advancement of the sport."