Most fighters arrive at the Contender Series hoping to prove they belong among the elite. Smilla Sundell turned up with a world title already in the rear-view mirror. The Swede became the youngest world champion in ONE Championship history at 17, outgrew the promotion, rebuilt herself as a mixed martial artist and left the Meta APEX in Las Vegas with a UFC contract the boss himself wasn’t sure she was ready for.
The Lowdown
Swedish, born in Sundbyberg on the northern edge of Stockholm. Fights as “The Hurricane” at Women’s Bantamweight and stands 5ft 10in. Unbeaten as a pro with a 3-0 MMA record, two of those wins by TKO. Behind that sits a 36-5-1 Muay Thai and kickboxing record with 23 knockouts, almost all of it built in Thai stadiums and ONE Championship rings. Spent the best part of six years at Fairtex in Pattaya before switching to Diaz Combat Sports. Signed with the UFC after beating Aline Pereira on the Contender Series on 13 October 2026.
Karate, a Holiday and an Island With Little Else to Do
Sundell’s parents put her in karate at five, purely for self-defence. Muay Thai came later, on a family holiday to Thailand when she was 10 or 11.
Then the whole family moved to Ko Samui for her parents’ work when she was 12. The island didn’t offer much in the way of organised sport. It had plenty of Muay Thai gyms. Smilla and her younger sister signed up at Yodyut Muay Thai.
She liked the training. Fighting was another matter. Sundell told ONE Championship that her parents entered her into her first fight with barely any warning, and the 12-year-old was far from impressed. She fought anyway. A steady run of bouts in the island’s stadiums followed.
The Girl Who Stayed Behind
At 15, her family packed up and went home to Sweden. Sundell stayed.
She had run out of opponents on Ko Samui and had been studying Stamp Fairtex. In October 2019, she moved to Pattaya and into the Fairtex Training Center, where she lived and trained until 2025. The sparring partners included Stamp, Rodtang, Wondergirl and Saemapetch, which is about as rough a finishing school as a teenage striker could ask for.
The wins piled up. She beat decorated Thai champion Sawsing Sor Sopit in Bangkok in October 2020 and even took a win over a male opponent, Bongsak Sitpholek. ONE Championship signed her at 16, by which point she was already 31-5-1.
Gold in Singapore at 17
Her ONE debut came at ONE: Full Circle on 25 February 2022. Australia’s Diandra Martin hit the canvas three times before the referee waved it off in round three. It was the first time Sundell had fought in four-ounce gloves.
Two months later she was fighting for a world title. Filipino-American Jackie Buntan had promised to expose the teenager’s carelessness over five rounds. Sundell walked her down for 15 minutes in Singapore on 22 April 2022 and took a unanimous decision to become the inaugural ONE Women’s Strawweight Muay Thai World Champion.
She was 17 years and 161 days old, which Guinness World Records lists as the youngest ONE Championship world champion on record. A $50,000 Performance of the Night bonus came with it, and so did ONE Super Series Female Fighter of the Year honours for 2022.
She outpointed Milana Bjelogrlić in her kickboxing debut in May 2023. Then came a clash of champions with Allycia Hellen Rodrigues, ONE’s Atomweight Muay Thai queen, at ONE Fight Night 14 on 29 September 2023. Sundell broke her down with punches and elbows for a third-round TKO and banked a second $50,000 bonus.
Lost on the Scales, Won in the Ring
Signed at 16, Sundell kept growing. Ahead of her second title defence she told Sportskeeda she had put on muscle and grown taller, and making 125lb became a fight of its own.
Before facing Natalia Diachkova at ONE Fight Night 22 in Bangkok on 4 May 2024, she weighed in at 126.5lb, a pound and a half over the Strawweight limit. She was stripped of the belt, and only Diachkova could win it.
Sundell folded her anyway, with knees and punches to the body, in the second round.
ONE had nowhere bigger to put her. In August 2025 the promotion released her, with her weight having outgrown the heaviest women’s division it offered.
Knees and Elbows in Las Vegas
Sundell signed with Las Vegas promotion Tuff-N-Uff in October 2025 and moved her training to Diaz Combat Sports, Ryan Diaz’s gym in Vancouver, putting grappling and jiu-jitsu front and centre. Her planned December debut fell apart when opponent Zurina Turrey wasn’t medically cleared.
She finally got in there on 22 January 2026 at Tuff-N-Uff 151, battering Miranda Barber with knees and elbows until the referee jumped in at 4:54 of the first round of a 150lb Catchweight bout. Dana White noticed and praised her publicly.
In June she made her Bantamweight debut at Tuff-N-Uff 154 and needed just 1:28 of the second round to stop Maya Stewart with punches and knees.
The Night Dana White Got Outvoted
The Contender Series handed her a high-profile assignment for its Season 10 finale on 13 October 2026. Across the cage stood Aline Pereira, sister of former two-division UFC champion Alex Pereira and a Karate Combat titleholder with more MMA fights under her belt.
Sundell marched forward from the opening bell, throwing combinations and digging in clinch knees. Pereira had her moments, landing counters and a stiff jab, and took her down in the third round. Sundell scrambled back up and went straight back to work. All three judges scored it 29-28.
The contract was no formality. White told her she had dominated but felt she had time to gain more experience elsewhere. Matchmaker Mick Maynard saw a serious talent in the women’s division and dug his heels in, and White admitted he had been outvoted before welcoming her to the UFC.
Unfinished Business on the Mat
Sundell was blunt about her own night’s work. She admitted she had hunted the knockout and missed too often, and said she wants a gradual UFC climb with grappling as a daily priority. She drills on the mat every day and enters jiu-jitsu tournaments to rack up live rounds.
Her long-term target is whoever happens to be wearing the Bantamweight belt by the time she gets there.
Smilla Sundell MMA Record and Fighter Stats
Name
Smilla Sundell
Nationality
Swedish
Weight Class
Women’s Bantamweight
Date of Birth
12 November 2004 (Age 21)
Height
5’10”
Pro Record
3-0 (2 wins by KO)
UFC Record
0-0
Recent Fight Record
DateEventOpponentResultMethod
13-Oct-26Contender Series 2026Aline PereiraWUnanimous Decision
5-Jun-26Tuff-N-Uff 154Maya StewartW2nd Round TKO
22-Jan-26Tuff-N-Uff 151Miranda BarberW1st Round TKO
👉 Explore: Fightomic Rankings | Fightomic Women’s Bantamweight Rankings