A Brisbane teenager is preparing for a 70-kilometre kiteboard journey to Moreton Island to raise money for a cancer support charity.

A Brisbane teenager is preparing to become the youngest person to cross Moreton Bay on a kiteboard.

Millie Brand, 16, hopes to make the return journey to Moreton Island from the southeast Queensland coast in about four weeks.

The total distance covered is estimated to be about 70 kilometres, and aims to raise $7500 for cancer support charity Redkite.

While the teenager has been kiteboarding for only two years, she said she was confident about the crossing and had been preparing outside school hours.

“I’ve just been trying to kite as much as possible, and I’ve been doing a little bit of running as well,” Ms Brand said.

“As far as we know, nobody else has done this before.”

The details of the journey, including the departure point, will be decided based on weather conditions closer to the five-day window set aside for the crossing.