Mandal was selected in Nepal Under-19s fourteen man squad in the 2008 Under-19 World Cup,making six Youth One Day International appearances in the tournament. In 2010, Mandal was selected in Nepal's fourteen man squad for the 2010 World Cricket League Division Five in February 2010, making his senior debut in the tournament in a controversial match against the United States. Both teams would progress to the final of the tournament, where Mandal made his second appearance of the tournament. In April of that year, he played for Nepal in the 2010 ACC Trophy Elite, making six appearances. Having gained promotion in the World Cricket League by winning Division Five earlier in 2010, Nepal played in the Division Four in August of that year, with Mandal selected as part of Nepal's fourteen man squad for the tournament, where he made seven appearances. In November 2010, he played for Nepal in the 2010 Asian Games, making three appearances against Hong Kong, the Maldives and Sri Lanka, though Nepal didn't progress far enough in the tournament for Mandal to become a medalist.
Just over a year later, in December 2011, Mandal played for Nepal in the 2011 ACC Twenty20 Cup, making five appearances. Nepal finished the tournament in fourth place and therefore qualified for the 2012 World Twenty20 Qualifier in the United Arab Emirates. In February 2012, he was selected as part of Nepal's fourteen man squad for the World Twenty20 Qualifier, making his Twenty20 debut during the tournament against Afghanistan. He made five further appearances during the tournament, with his final appearance coming against Papua New Guinea. He scored 124 runs at an average of 20.66 in his six matches, with a high score of 50. This was his only half century score in the tournament and came against Afghanistan. Nepal finished the tournament in seventh place, therefore failing to qualify for the 2012 World Twenty20.
In August 2012, he was selected in Nepal's fourteen man squad for the World Cricket League Division Four in Malaysia. He made six appearances in the tournament, scoring 186 runs at an average of 37.20, with a high score of 113 made against Denmark. Nepal won the tournament, in doing so they qualified for the 2013 World Cricket League Division Three.
Mandal was in, and out of the team for quiet a while. He again made a comeback to the team with some solid performances in the domestic 50-over tournament of Nepal. He scored three centuries, and a half-century in seven matches scoring an outstanding 429 runs at an average 61.29 in that tournament. That made him the record highest scorer in the domestic circuit, and also the player with maximum number of centuries, four centuries.
Mandal's best performance came against Scotland at Ayr in ICC WCL Championship. He slammed 100 runs of just 93 balls including eight fours and a six, though that was not enough for Nepal as Nepal lost the match by three runs. In doing so, he became the first Nepal batsman to score a List A hundred. He now has two international centuries to his name.