2018 Diema Xtra Sofia Open

The 2018 Sofia Open (also known as 2018 DIEMA XTRA Sofia Open for sponsorship reasons) was a men's tennis tournament played on indoor hard courts. It was the third edition of the Sofia Open as part of the ATP World Tour 250 series of the 2018 ATP World Tour. It took place at the Arena Armeec in Sofia, Bulgaria, from 5 February until 11 February 2018. Unseeded Mirza Bašić, who entered the main draw as a qualifier, won the singles title.

Singles

 * 🇧🇦 Mirza Bašić defeated 🇷🇴 Marius Copil, 7–6(8–6), 6–7(4–7), 6–4

Doubles

 * Robin Haase / Matwé Middelkoop defeated  Nikola Mektić / 🇦🇹 Alexander Peya, 5–7, 6–4, [10–4]

Seeds

 * 1 Rankings as of January 29, 2018

Other entrants
The following players received wildcards into the singles main draw:
 * 🇧🇬 Adrian Andreev
 * 🇧🇬 Alexander Donski
 * 🇧🇬 Dimitar Kuzmanov

The following players received entry from the qualifying draw:
 * 🇧🇦 Mirza Bašić
 * Ernests Gulbis
 * 🇸🇰 Martin Kližan
 * 🇸🇰 Jozef Kovalík

The following players received entry as a lucky loser:
 * 🇮🇹 Salvatore Caruso
 * 🇩🇪 Florian Mayer

Withdrawals

 * Before the tournament
 * 🇧🇬 Grigor Dimitrov (shoulder injury) →replaced by Stan Wawrinka
 * 🇦🇺 Matthew Ebden →replaced by 🇩🇪 Florian Mayer
 * 🇰🇷 Chung Hyeon (blisters) →replaced by Blaž Kavčič
 * 🇷🇸 Filip Krajinović →replaced by 🇨🇾 Marcos Baghdatis
 * 🇰🇿 Mikhail Kukushkin →replaced by 🇮🇹 Salvatore Caruso
 * Lu Yen-hsun →replaced by 🇹🇳 Malek Jaziri

Seeds

 * 1 Rankings are as of January 29, 2018.

Other entrants
The following pairs received wildcards into the doubles main draw:
 * 🇧🇬 Alexander Donski / 🇧🇬 Alexandar Lazov
 * 🇧🇬 Dimitar Kuzmanov / 🇧🇬 Vasko Mladenov

The following pair received entry as alternates:
 * 🇧🇬 Radoslav Shandarov / 🇧🇬 Vasil Shandarov

Withdrawals

 * Before the tournament
 * 🇰🇿 Mikhail Kukushkin