Japan sent a group of 10 staff officers to the headquarters of UNTAET and UNMISET from February 2002 to May 2003, and it sent a second group of 7 staff officers from April 2003 to June 2004. Stationed in the headquarters in Dili, the capital of East Timor, the personnel were involved in planning and coordination for the maintenance and repair of roads and bridges and other logistic support.

From March 2002 to June 2004, four engineer units with a maximum of 680 personnel at one time were successively sent to East Timor. With their headquarters in Dili, the engineers were billeted in four locations: Dili, Maliana, Oecusse, and Suai. They engaged in logistic support for UNMISET, including maintaining and repairing roads and bridges and maintaining and overseeing water supply points, and they also took part in civilian support projects, such as landscaping the grounds of elementary schools.

The SDF personnel in these engineer units included women, who were dispatched for the first time because, as has been observed in UN and other forums, the role of women in peacekeeping operations needs to be expanded.

A liaison and coordination office was set up in Dili and staffed with several liaison and coordination personnel from the Cabinet Office. Their job was to provide liaison and coordination between Japanese staff officers and units and relevant organizations so that the staff officers and units could perform their duties smoothly and effectively.

To assist the engineer units and staff officers dispatched to East Timor starting from February 2002, the Maritime Self-Defense Force transport ship Osumi and escort ship Mineyuki and six Air Self-Defense Force C-130H transport planes transported engineer units and some of their equipment. About twice a year, C-130H transport planes flew in food supplies for the engineers and staff officers.