When is classification needed, and from what age?

Paralympics Australia's classification FAQs say classification is not needed for social play, but it is required for competitive Para sport. Swimming and athletics allow school-level classification from age eight. Most other sports start between ages twelve and sixteen.

For international classification, each federation sets its own minimum age, location and timing. Places are limited and may be prioritised.

Source: https://www.paralympic.org.au/classification/classification-faqs/