Yumnam was included in The Guardian's 2020 edition of their list of 60 footballers for the next generation in October 2020.
He made his I-League professional debut for Indian Arrows on 5 February 2020, at Tilak Maidan against NEROCA FC, he started and played full match as they drew 0–0.
[1] On 16 January 2023, Yumnam joined Indian Super League side Chennaiyin on a permanent deal.
[3] On 19 January 2025, Kerala Blasters announced the signing of Yumnam from on a long-term deal, which would keep him at the club until 2029.
[4] Bikash was part of the Indian U-16 team that reached the quarterfinals of the 2018 AFC U-16 Championship in Malaysia.