| Date: | 14–20 January |
| Edition: | 3rd |
| Surface: | Hard (indoor) |
| Location: | Koblenz, Germany |
| Champs: |  Gianluca Mager |
| Champd: |  Zdeněk Kolář / Adam Pavlásek |
The 2019 Koblenz Open was a professional tennis tournament played on indoor hard courts. It was the third edition of the tournament which was part of the 2019 ATP Challenger Tour. It took place in Koblenz, Germany between 14 and 20 January 2019.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 Norway | Casper Ruud | 111 | 1 | |
| Yannick Maden | 125 | 2 | ||
 Russian Federation | Alexey Vatutin | 175 | 3 | |
| Italy | Andrea Arnaboldi | 178 | 4 | |
| Daniel Brands | 183 | 5 | ||
 United Kingdom | James Ward | 187 | 6 | |
 Sweden | Mikael Ymer | 196 | 7 | |
 Belgium | Arthur De Greef | 200 | 8 | |
| Czech Republic | Adam Pavlásek | 203 | 9 | |
| Tobias Kamke | 214 | 10 | ||
 Slovakia | Filip Horanský | 218 | 11 | |
 France | Kenny de Schepper | 219 | 12 | |
| Czech Republic | Zdeněk Kolář | 220 | 13 | |
| Tallon Griekspoor | 234 | 14 | ||
| Thiemo de Bakker | 243 | 15 | ||
 Belarus | Uladzimir Ignatik | 256 | 16 |
The following players received wildcards into the singles main draw:
Marek GengelThe following player received entry into the singles main draw using a protected ranking:
The following players received entry into the singles main draw using their ITF World Tennis Ranking:
Javier Barranco Cosano Raúl Brancaccio Roman SafiullinThe following players received entry from the qualifying draw:
The following players received entry as lucky losers:
Riccardo BonadioSee main article: 2019 Koblenz Open – Singles.
Gianluca Mager def. Roberto Ortega Olmedo 2–6, 7–6(8–6), 6–2.See main article: 2019 Koblenz Open – Doubles.
Zdeněk Kolář / Adam Pavlásek def. 
Jürgen Melzer / Filip Polášek 6–3, 6–4.