SWIS was built to relieve the pressure of a growing student population at both South Whidbey Elementary School and (at the time) Langley Jr. High School. Previously, both LJHS and SWES had an extensive network of portable buildings to be able to accommodate students. After SWIS was opened, LMS moved all of its portable buildings to SWHS, and SWPS converted the portable for other uses, however, by 1990 SWPS was again using portables for classrooms. After only being used for 3 years, SWIS added a portable classroom in order to accommodate the growing student population. Behind the school is the remnants of a clearcut performed at the same time the area where the school it was cleared. This area was to be the location of a new South Whidbey Jr. High School, but the plans were scrapped after SWIS was redesigned with more classrooms for 5th grade students. The money made by the district in the sale of the lumber from the property partially paid for SWIS' construction.