See main article: 2018 Diema Xtra Sofia Open.
Viktor Troicki and Nenad Zimonjić were the defending champions, but lost in the first round to Robin Haase and Matwé Middelkoop.
Haase and Middelkoop went on to win the title, defeating Nikola Mektić and Alexander Peya in the final, 5–7, 6–4, [10–4].