United Airlines is adding new routes this summer to Croatia, Greece, and Iceland, all of which have announced policies allowing vaccinated travelers to visit without quarantine.

The carrier will begin three weekly flights to Dubrovnik on July 8 on Boeing 767-300ER aircraft, which will be the only nonstop service between the United States and Croatia, according to United. American Airlines had operated service between Philadelphia and Dubrovnik, but it ended that route as part of announced network plans last summer.

In addition, United on July 1 will begin daily service between Washington Dulles and Athens, using Boeing 787-8 aircraft, and between Chicago O’Hare and Reykjavik, using Boeing 757-200 aircraft. United previously has had summer service to both cities from Newark, and that service also will resume on June 3.

United reports that searches on its website for flights to all three countries increased 61 percent over the past month. All the new routes are subject to government approval and are scheduled to run through Oct. 3.