ANNAPOLIS, AUG. 7 -- Maryland's globe-trotting governor, William Donald Schaefer, will leave the country in the midst of his reelection campaign for another overseas trade mission.

Schaefer, along with a contingent of state officials, shippers and union leaders, will leave on Aug. 18 for an eight-day trip to Taiwan and Hong Kong. It will be Schaefer's third overseas excursion since May and the eighth since he took office.

While in Taipei, the Democratic governor will attend the signing of a multiyear lease between Evergreen Marine Corp. and the Port of Baltimore for use of the new Seagirt Marine Terminal. Evergreen now stops weekly at another terminal at the port, and officials said they did not know if the agreement will mean increased business for Baltimore immediately.

Schaefer will return about two weeks before the Sept. 11 primary, in which he is opposed by Anne Arundel County real estate agent Frederick M. Griisser Jr. In 1988, Griisser led the unsuccessful attempt to repeal a handgun control law that Schaefer backed.

Schaefer aides played down the timing of the trip today. "I think the governor is more concerned about running the affairs of the State of Maryland," press secretary Paul E. Schurick said when questioned about the trip's effect on the governor's campaign.

But Schaefer's reelection strategy seems to be focused on remaining above the fray. Schaefer, a favorite to win another term, calls his reelection effort the Campaign for Maryland, and at times it stages events encouraging volunteerism to the state that Schaefer doesn't even attend.

Schurick said planning for the Far East trip began about two weeks ago. He said he had no estimate on the cost to the state, but added that the nine private persons traveling with Schaefer will pay their own way.

Schaefer's 12-day trade mission in May to Eastern Europe and the Soviet Union cost the state about $200,000, Schurick said today. The price tag has not been totaled for his six-day June trip to Scandinavian capitals and other cities in Europe to promote the port and Baltimore-Washington International Airport.

The Far East mission had its genesis in June, when Y.F. Chang, Evergreen's chairman, toured the port with Schaefer and invited the governor to Taipei.

Schaefer said Chang had asked him personally to attend the signing. He said Chang had been insulted by former governor Harry Hughes's inattention to him during an earlier trip to Maryland, so Schaefer said he felt obligated to make the 18-hour journey rather than risk offending a man he describe as a "shipping giant."