Japan Air Lines Co. will begin flying nonstop from Washington Dulles International Airport to Tokyo on March 30, joining All Nippon Airways Co. and United Airlines in serving this rapidly growing international market.

Since 1986, when the first airline service link between the Washington metropolitan area and Tokyo was forged by All Nippon Airways (ANA), the increase in passenger and cargo service between the two world capitals has helped build both Japanese tourism and investment in the Washington area, according to airline and airport officials.

"We see a continuing strong market and a growing market," said Leo J. Schefer, president of the Washington Airports Task Force. "The fact that we're going to have competitive service on the route is going to stimulate the market further."

Travel between the United States and Japan is restricted by bilateral agreements that limit the number of cities served and the number of flights. The coming expansion in service is a result of increases negotiated between the two countries in 1989.

Prior to that, ANA provided the only nonstop service from here to Tokyo. The company started with three flights a week, later expanding to six as the market grew. "Right now we carry more than 100,000 passengers a year between the U.S. and Japan," said Yuki Miyagishima, ANA's manager of sales and marketing for the Washington area.

Most of ANA's passengers on the nearly 13-hour trip are Japanese, and a majority of those are tourists, said Miyagishima. Most of the U.S. travelers on ANA are flying for business purposes, he said.

Washington has proved to be a popular destination for Japanese tourists. A year after ANA began its nonstop service, Japanese tourism in the region increased by 260 percent, according the Washington Airports Task Force. Japanese investment in the area has increased, too, according to Schefer, who said that businesses from countries served nonstop from the Washington area are more likely to establish operations here. In 1988 and 1989, a total of 40 Japanese-affiliated businesses invested more than $200 million in Virginia, creating more than 2,000 jobs, according to the Virginia Department of Economic Development.

On Jan. 8, United Airlines, which flies from Washington to Tokyo with a stop in Newark, will begin offering a 16-hour and 30-minute flight that originates at Dulles and stops in Chicago before proceeding to Tokyo. Although United won't offer the benefit of nonstop service, the carrier should benefit from a U.S. law that requires government employees to use U.S. airlines when possible. Federal contractors also often are required to choose U.S. airline service for flights abroad.

JAL, which has flown into the Washington area occasionally bearing Japanese dignitaries but which has no scheduled service, will begin its service three times a week on March 30, assuming that the requisite government approvals are obtained. "We always start with a moderate number of flights," said Morris Simocelli, a spokesman for JAL. The airline believes Washington is an attractive tourist destination, he said.

One factor that increased the amount of service from the United States to Japan is the advent of smaller aircraft that make money flying long ranges, such as the 6,869-mile route between Washington and Tokyo, with fewer passengers, said the airport task force's Schefer. JAL said it will fly the route on a specially configured 268-seat Boeing 747-200.

The trip isn't cheap. United's lowest fare is $1,263 for a round trip. Its business-class fare is $1,512 one way and its first-class fare one way is $2,760.

ANA's advance purchase fare for weekday travel is $1,156 round trip and is available only during certain times of the year. The same fare for weekend travel is $1,263. ANA's business-class and first-class fares, such as United's, are $1,512 and $2,760, respectively, one way.

Although fares on international routes are less flexible and less subject to discounting than fares for domestic travel, more competition for those who would fly from the United States to Japan (including airlines that offer travel to Japan from other American hubs) may produce promotional discounts, said Schefer. "This is the summer to look for some good deals."