Lalremsiami was included in the squad for the 2018 World Cup as India's youngest player at 18. After strong performances in the league games, Lalremsiami scored her first and only goal of the tournament in the crossover match against Italy. Receiving an assist at the far post sent in off a long corner by Reena Khokhar, Lalremsiami scored off the reverse stick on seeing goalkeeper Martina Chirico advance, giving her side an early 1–0 lead. India advanced to the quarter-final after a 3–0 win. Facing Ireland in the quarter-final, her side lost in the penalty shoot-out and finished in the eighth place.