Rainbow Bay Picnic Site offers day-use access to Lake Granby's southwest shore with picnic tables and fire grills, accommodating approximately 20 vehicles.

A daily use fee ($5/day, $10/3-day, $15/7-day, or $30 annual pass) is required, and the site provides a convenient launch point for fishing and paddling activities. Note that restrooms and potable water are not available at this location.