The National title is decided by a combination of points over three events held from Friday to Sunday.
Nevatt said she was pleased with how the event had gone, having netted her first national record in two years.
"My overall points total was a personal best which will be hard to beat.
"But one of the beautiful things about freediving is there are no limits, over time your body continues to adapt and you continue to improve, even if the improvements become fewer and further apart as you start to reach your maximum."
Freediving is a water-based breath holding sport, essentially snorkelling taken to an extreme.
In pool competitions divers attempt dives based on horizontal distance swum underwater (dynamics) and time based breath holds (statics).
Depth events are held over summer in open water where divers reach great depths and return on a single breath.
The body experiences a dive response which allows divers to naturally conserve oxygen due to lowered heart rate, spleen contraction and vasoconstriction, enabling them to hold their breath for long periods of time and stay conscious.
Freediving can be dangerous if practised alone or without proper instruction due to the risk of blacking out, and a course or introductory session with a freediving club is highly recommended.
Clubs offer intro evenings for beginners keen to try it out.
"Most beginners surprise themselves and can hold their breath between about two and four minutes in their first session," Nevatt said.
"We build them up slowly and the time just disappears, so they're always surprised when we tell them how long they've been under."