New rules at airports in Bulgaria Bulgarian citizens travelling in the Schengen region are only subject to airport security checks as of midnight on March 31, they are no longer subject to passport control.
The passport control counters that were once present at Sofia Airport have been replaced. In other words, travelers will go through airport security (baggage check) following check-in. From the sleeves, flights to the Schengen region will be managed. Additionally, passports will be checked at the concourse's base, where counters will be operational.
Children will be able to travel in the Schengen area without a declaration of consent from a parent.

For departing
When visiting a nation that is a part of Schengen, the airport stated that after checking in your bags, there is simply a security check. After that, you proceed to your departure gate bypassing passport control. Liechtenstein, Norway, Iceland, and Switzerland are also members of Schengen. Customs controls apply to citizens traveling to non-EU nations as well as those passing through a Schengen member state on their way to third countries.
The airport reminds you that the travel process is unchanged whether your destination is a non-Schengen nation: check-in, security check, customs control, and passport control.

For arrivals

If you have checked in baggage and are arriving from a Schengen member nation, you can skip passport control and proceed straight to baggage claim upon landing. Customs control applies to travelers coming from non-EU nations as well as travelers arriving from third countries via a Schengen nation.