WASHINGTON — Alaska Air Group Inc., awaiting approval for its $2.6 billion acquisition of Virgin America, is adding nonstop service from BWI Marshall Airport to San Diego next spring.

It is the fourth East Coast destination the company has added from San Diego since 2012. On Monday, service begins in Newark, New Jersey, Orlando and Boston.

Alaska Airlines’ BWI Marshall to San Diego service will start March 15 with a 6:15 a.m. daily departure on Boeing 737 aircraft. The San Diego to Baltimore flight departs daily at 10:55 p.m.

“Our San Diego customers will soon enjoy nonstop flights to this historic seaport city, as well as easy access to the nation’s capital nearby,” said Alaska Airlines vice president of capacity planning.

Alaska Airlines’ BWI Marshall to San Diego service will compete with Southwest Airlines, which offers two, daily nonstop flights from BWI Marshall to San Diego.

Alaska Air began service at BWI in September 2014 with daily nonstop flights to Seattle. Last year, it added nonstop flights from BWI to Los Angeles.