Sunaba comes from a Kyokushin Karate background were she was she was a contender for the Japan college National Championship. She has fought in notable promotions such as Smackgirl, Valkyrie, Pancrase, Shooto, Bodog Fight, and DEEP. She holds notable victories over Misaki Takimoto, Emi Tomimatsu, Emi Fujino, Mari Kaneko, and Sadae Suzumura.

Tomomi won her debut against Mari Kaneko but lost her 2nd fight by DQ for a soccer kick.  Next she would enter the Smackgirl: 2002 Japan Cup 2002 Middleweight Tournament. She would sub her first opponent but drop a decision in a rematch with Kaneko. She next fought the tournament champion Yuka Tsuji, she would lose by armbar. After a shaky 1-4 slide Tomomi moved to Pancrase.

In Pancrase she began to find her groove winning her first fight TKO, defeating Takimoto by decision, and winning 3 more fights. This set up the rematch with Tsuji. The winning streak would be snapped when Tsuji subbed Sunaba with a Rear Naked Choke. A few fights later she took on rising star Rosi Sexton. In an unfortunate accident Sunaba got her right foot tangled up during a ground transition with Sexton and seriously injured her right ankle; dislocating it and losing the fight by TKO. The injury was so horrific that even fighters watching the match were shocked. Sunaba immediately received medical assistance and was airlifted to a hospital, being operated on in the same day. Afterwards, Sunaba was hospitalized in Japan for four months and received more surgeries due to complications with the screw anchorage and osteomyelitis.

After almost a year without fighting, Sunaba returned at Pancrase 2008 Shining Tour defeating Emi Tomimatsu by TKO via leg kicks. She would drop her next fight to top prospect Rin Nakai via TKO. She then entered the 2009 Valkyrie Featherweight Tournament but would suffer defeat via Rear Naked Choke in the opening round. This would start a losing slide for Sunaba in which she would draw with Izumi Noguchi who she drew with a decade prior in Kickboxing, a loss to Miku Matsumoto, and Megumi Fujii.

Sunaba got back on the winning path by beating Masako Yoshida to avenge a loss to her earlier in her career. She would win her next three fights including a flying headkick KO over Elisabete Tavares. She next fought the final Valkyrie Featherweight champion in Mei Yamaguchi, dropping a decision. She next defeated a top prospect in "Manhoef" Suzumura.

Sunaba retired from combat sports in 2012 after 13 years of Kickboxing and MMA competition. Her retirement fight was on March 11, 2012 at Pancrase: Progress Tour 3 against JEWELS mainstay Saori Ishioka losing by armbar.

In addition to MMA Sunaba had a successful career in Kickboxing sporting a record of 12-5-2. She also is 0-1 in Muay Thai. She participated in 2011 Shoot Boxing Girls S-Cup Tournament losing in the opening round by majority decision.