"It's got some amazing parts, some scary parts, a lot of emotional ups and downs with the competing side. And you need your wits about you 24/7."
Janine, 52, and Dean, 56, taught Ella to surf at age 4 at Raglan. By 6 she was competing in under-12 contests around the country alongside big brother Braedon.
At 8 Ella scrawled on a surf poster she wanted to be the world champion and put it up on the wall beside her bed - "so every day when I woke up I saw it".
In 2013 at Brazil's Joaquina Beach she became the only Kiwi to win the women's world junior championships title.
"It was life-changing," Ella said.
Returning home, she was greeted by lines of surfers holding their boards to form a guard of honour into a civic reception on Whangamata's main street.
"They made me feel like a queen".
Turning professional, she has spent the past four years on the World Surf League's women's qualifying series, hoping to crack the championship tour.
Ella's journey has to taken her to Australia, Brazil, El Salvador, Nicaragua, Panama, Peru, Costa Rica, Morocco, Japan, France, Spain, Portugal, China and the United States.
After Mexico, this year's diary includes Barbados, Martinique, South Africa, five contests around Europe, then Japan.
Competitive surfing is incredibly demanding. Conditions constantly vary and competitors have to be ready to negotiate gentle swells to giant waves.
"When you're doing other sports or other things in life, sometimes you have a choice to say no I don't want to go that far," Ella said. "[But] when you put yourself in the water, you've made a decision.
"So when those 10-foot sets come through, mentally and physically it teaches you a lot of things about your body and how to deal with that pressure."
"The power of the wave, how hard it's going to hit you, how long can you hold your breath for, how calm can you be when you're under [water]? Is there reef underneath?
"You've got to face it head on."
But the thrill is intense and addictive.
Inside the barrel of a wave, "it's like time slows down". "You think the water's blue when you look at it on land, and then when you're actually immersed in it it's so much bluer. It's pretty surreal."
To hone her 1.78m, 70kg frame for the power and resilience needed to cut it at elite level, Ella lifts weights, runs stairs and does spin classes for up to three hours, six early mornings a week.
Hours of surfing through the day are followed by boxing sessions at night. She enjoys fight-game training and "probably would" hop in the ring for a competitive bout.
She has been vegan for the past seven months, and said it has re-energised her.
Her hectic lifestyle precludes a relationship. "When the right guy comes along" he wouldn't have to be a boardrider. But "I'll get him into surfing though", she said laughing.
Dean and Janine take turns accompanying their daughter around the globe. Older brother Braedon, 27, a former national-level surfer runs their landmark Whangamata Surf Shop while they are away.
Her proud parents have shared Ella's highs. Janine was with her in Brazil when she shook the surfing world by capturing the junior title.
They have also watched out for her during some scarier moments.
Travelling to El Salvador for the first time with his daughter, Dean had been "freaking out" after learning it had one of the highest homicide rates in the world.
Driven to a hotel in the dark of night, he was unsure exactly where they were and concerned to see "all these people outside drinking".
"We were in a room, I could hear these guys outside. I went, I'm not liking this. I ended up putting a closet up against the door."
There was a gang-related murder that night not far away, Dean said. When they made it to the contest, the area was locked down by the military.
In Nicaragua he repelled a 4-foot snake invading their rooms. "I was fighting with [it] with my surfboard."
There are around 500 women in this year's World Surf League qualifying series. Ella is currently in 36th spot.
It costs from $30,000 to $50,000 a year for her to travel the circuit trying to graduate to the 17-strong championship tour, she said. Her sponsors include Rip Curl, Ocean & Earth and Whangamata Surf Shop.
When Ella's at home she works at the family business. The Williams took over the shop in 2002, and which continues to serve holiday-makers at the Coromandel beach holiday hotspot.
Ella has 92,000 followers on Facebook and 18,000 on Instagram.
With surfing at the Olympics for the first time, at Tokyo in 2020, Ella has an extra goal. She attended a Surfing New Zealand high performance camp in April and is "100 per cent" committed to making the Olympic team.
The poster she put on her bedside wall 15 years ago has been supplemented by a wristband with the inscription "Ella Williams: Imagine, Dream, Believe".
"My motto my whole life has been to imagine big things, dream big and always believe in yourself... [The] world title's definitely coming my way."