ESAA English Schools' Athletic Association Age Groups explained.

The age limits for ESAA Cross Country Championships, Track & Field Championships, and Combined Events Championships are:

Junior 13 years and under 15 years of age on 31st August at the end of the current school year
Intermediate 15 years and under 17 years of age on 31st August at the end of the current school year
Senior 17 years and under 19 years of age on 31st August at the end of the current school year

The age limits for ESAA Schools Cup competitions are:

Junior 12 years and under 14 years of age on 31st August at the end of the current school year
Intermediate 14 years and under 16 years of age on 31st August at the end of the current school year

Notes relating to all competitions
The school year is deemed to run from September to July, so August at the end of current school year is the August following the end of the summer term, irrespective of whether some schools actually start their new year in August.
Although the Combined Events Final is held in September it is considered to be in the same school year as the previous regional rounds which lead up to the final, thus age limits are those which apply at the time of the regional round.

Athletes may only compete in the age group corresponding to their age. In particular this means:

athletes cannot compete in a higher age group
athletes who are younger than the Junior age group cannot compete.

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