From there his parents Sisira Kumara and Ramani Jayasundara noticing his talents in volleyball and to give him a sound education Isira was admitted to Grade Six of his new school National College Dambulla. Immediately he came under their volleyball coach Madushanka Ratnayake.
They participated for the Divisional and, Zonal tournaments and came first and in the provincial tournament they were the runners up and participating in all island under 15 DSI Tournament they could not come up to expectations In the All Island National School Tournament they lost and in the following year in the lower level tournaments once again they lost the under 17 DSI tournament match to Rajasinghe Maha Vidyalaya Ruwanwella and in the under 17 All Island Volleyball National Tournament too they could not come up to expectations.
Then in the All Island National Schools too they lost and to enhance the skills of the game he joined Dhammissara National School Nattandiya in 2018 and no sooner he came under their coach Channa Jayasekera and winning the all lower level tournaments they were the runners up of the DSI All Island under 19 tournament. With the outbreak of Covid 19 his volleyball came to a standstill.