Lomb began his career in the youth of the SC West Cologne, before he joined Bayer 04 Leverkusen for the 2008/09 season. From the B- Youth ( U -17) played Niklas Lomb total of four seasons in the youth of the working self. For the season 2012/13 he enlisted as a third-choice goalkeeper behind Bernd Leno and Michael Rensing in the senior squad on. In order to gain match practice, he is also a regular keeper of the second team (U -23), which competes in the fourth division Regionalliga West.
His professional debut was Lomb in their final group game in the Europa League on 6 December 2012 compared Rosenborg Trondheim.