The 2018 Koblenz Open was a professional tennis tournament played on indoor hard courts. It was the second edition of the tournament which was part of the 2018 ATP Challenger Tour. It took place in Koblenz, Germany between 16 and 21 January 2018.
The following players received wildcards into the singles main draw:
The following players received entry into the singles main draw as alternates:
The following players received entry from the qualifying draw:
