The Vandals (17-12, 8-5 Western Athletic) used a 24-9 run in the first half to take a commanding 42-24 lead.
Zane Johnson scored 18 points and Joston Thomas 16 to lead the Rainbow Warriors (15-14, 6-7), who dropped their fourth straight.
Idaho shot 51 percent from the field and made 10 of its 21 3-point attempts, while Hawaii was just 35 percent on field goals. The Vandals outrebounded the Rainbow Warriors 46-27 and made 20 of 25 free throws.
Hawaii's Vander Joaquim, who led the team with an average of 14.8 points per game entering the contest, was held to a season-low four points.
The Vandals led 45-27 at the break.
- The Vandals