Ukraine and Bulgaria Sign a 10-Year Security Deal — and Here Is What Sofia Gets Out of It

Bulgaria has signed a decade-long security agreement with Ukraine covering drone co-production and air defence funding. Here is what both countries gain from this unexpected partnership.

Bulgaria's security relationship with Ukraine has been complicated by the country's domestic political divisions about Russia — divisions that produced multiple government changes since 2022 and that have made Sofia a less consistent Ukraine supporter than its Eastern European neighbours. The 10-year security agreement signed on March 30 represents the current Bulgarian government's most definitive commitment to Ukraine's security and simultaneously a significant step in building Ukraine's defence export relationships with EU member states.

The agreement's specific contents — Sofia committing to help fund Ukrainian air defences and to co-produce arms including drones — reflect the specific capabilities that Bulgaria can offer and the specific needs that Ukraine has. Bulgarian defence industry has particular expertise in Soviet-calibre ammunition production and in certain electronic systems whose production is compatible with Ukrainian requirements. Co-production arrangements that leverage existing Bulgarian industrial capacity while incorporating Ukrainian design and systems integration create value for both parties.

For Bulgaria, the agreement serves several functions simultaneously. It demonstrates credibility to NATO allies who have noted Bulgaria's inconsistency on Ukraine support. It creates access to Ukrainian drone technology that Bulgarian defence planners see as directly relevant to Bulgaria's own defence needs, given its Black Sea coast and the proximity of Russian naval operations to Bulgarian territory. And it creates commercial relationships that Bulgarian defence industry can leverage for future export revenue.

For Ukraine, the Bulgarian deal is one piece of a broader strategy of building bilateral security relationships with EU member states that goes beyond the arms donations that characterised the early war period and into the territory of genuine defence industrial partnership. These partnerships serve Ukraine's long-term interest in building a sustainable, internationally networked defence industrial base rather than dependence on any single partner's generosity.