"You can't do everything all the time and I think I've just started to realise that," she said.
"I love the surf and have grown up with it, but the Olympics is a really big drawcard.
"I'm going to follow my dreams. I've got to put in a lot of hard work to get there, but I'm ready for that."
The Alexandra Headland talent is a relative newcomer to kayaking, but has impressed national coaches.
With little preparation, she finished eighth in the K4 500 at the 2013 junior world championships.
This year she finished eighth in the K1 500 open women's final at the national championships and recently claimed fifth place in the K2 500 at the under-23 world championships.
Upon returning from that meet she started training hard for this weekend's Kellogg's Nutri-Grain Ironwoman trials.
She will withdraw her nomination, however, having decided to focus wholly on kayaking.
That decision came after national coaches told her she was a genuine prospect.
"They made me realise that if I start to work harder with kayaking that I would be an asset to their team," Bull said.
"I thought about it long and hard and discussed it with a lot of different people and it seems like now is the time to start to really focus on it."
Bull will concentrate on next year's national championships, where kayakers will be selected for the world championships in Italy.
It is there that Australia will attempt to qualify boats for Rio. A strong performance would put Bull into the box seat for the Games.
Bull's decision brings an end to a short but highly promising surf lifesaving career.
She won a round of the ironwoman series at Noosa Heads last year, finished 10th overall in the 2012-13 series and 12th overall in 2013-14.
She is also last year's winner of the Coolangatta Gold short course event, after winning the Gold junior races in previous years.
Bull will not completely stop her involvement in the sport. The under-19 national ski champion, she will compete at carnivals, including the state and national championships, in ski and maybe board events.
And she will likely be an equipment handler for brother Sam if he makes it into the ironman series.