Delta will offer service to Croatia for the first time this summer.
The carrier's flights from New York JFK to Dubrovnik will depart four times weekly beginning July 2.
Delta is joining United in putting Croatia on its route map this summer as a result of the country's decision to open to U.S. travelers who can provide proof of Covid-19 vaccination, proof of recovery from the virus or a negative Covid-19 test result.
The move follows decisions by Delta to resume and add service to Iceland and Greece after those countries announced openings to U.S. travelers. Iceland requires travelers to be vaccinated, while Greece will accept proof of vaccination or proof of a negative PCR test within 72 hours of departure.
Delta will fly to Athens this summer from New York JFK and Atlanta and to Reykjavik, Iceland, from JFK, Minneapolis and Boston.