Isak played in the NECS Cup for Bawngkawn LC, and was later moved up to Bengaluru FC, in 2018/19 season he was signed by Aizawl F.C. from Electric Veng FC.[1] He made his professional debut for the Aizawl against Chennai City F.C. on 16 November 2018, He was brought in as substitute in the 69th minute as Aizawl lost 1–2.[2]
On 7 March 2024, Vanlalruatfela received first call-up to the national squad of India as one of the 35 probables by head coach Igor Štimac, for the both home and away games against Afghanistan in round 2 of the 2026 FIFA World Cup qualifiers.[5]