She is a housewife. She has a 15-year-old son Swayam. She works in the cultural department of the Gorkhaland Territorial Administration (GTA). Her husband Suren Tamang owns a taxi and operates between Darjeeling and Singamari. Still, after handling all the everyday tasks, Sunita Subba has inscribed her name in the field of Indian marathon, only within a span of six years. 

The 32-year-old female marathoner hogged the limelight when she won the 122km marathon last September that takes place at the world's highest altitude. The race is called Silk Route Ulta Ladakh Marathon. It starts from a village named Kayagar at 10 thousand feet and ends in Leh which is situated at 11, 400 feet via Khardungla pass at 18 thousand. This is the world's one of the toughest marathon and the runners are generally needed 22 hours to complete the 122 km distance as it starts at 7 pm and gets completed at 5 pm the next day. 

Sunita who resides in Darjeeling started long-distance running in 2016. In her first marathon held in Darjeeling, she finished in the 34th spot. But that triggered her to fall in love with the event and she also got encouragement from her niece Smita. Darjeeling has no such infrastructure where marathoners can practice. Additionally, there is no trained coach in the event there in the district. Indomitable Sunita did not give up. Even without a coach, she runs in the hilly region, even on the rugged land. Sometimes, Sunita practices running for 160 kilometers up and down between Darjeeling and Siliguri through the roadside at the usual risks. The iron lady got the result also, winning Sandakphu Marathon (65 kilometers) twice in 2021 and 2022 and then the Delhi marathon (104 kilometers). 

But Sunita's opposition is not only distance. She has to fight continuously with the financial crisis. Speaking over the phone from Darjeeling Sunita commented, "You need financial support to participate in marathons. My total expense for the Ladakh marathon reached nearly Rs 70 thousand. My sister and her husband helped me a lot. I also got some favor from a few of my well-wishers. But how can I continue in this way? I do not have a sponsorship."

Sunita recently overcame another acute hurdle when she despite the cracks on her right ankle, won the Mumbai marathon on 22nd January this year, winning 100 miles (161 kilometers) in 27 hours. 

Sunita said, "One of my well-wishers, a marathon coach from Bangalore asked me not to run in Mumbai. But as my registration fee was deposited and they had already made an advertisement on social media, I took part. I felt severe pain while running as the roads were as usual jagged. But I could not give up till the last." Sunita thanked her GTA  executive director Samden Dukpa and assistant director Bhupendra Khanta Ghishing for allowing her to participate in the marathon.