Some good online summer school programs include those available from K12, International Connections Academy and Apex Learning. All three of these schools offer accredited courses, including some that may be applied toward credit at the student's local high school.
K12 has online summer school classes in core subjects, foreign languages and personal enrichment areas, and credit recovery courses are available for high school students who need to retake courses from their own high schools.
International Connections Academy has kindergarten through 12th grade summer school courses. In addition to the core courses, technical education courses and credit recovery courses for high school students, kindergarten through eighth grade students can study reading, math or foreign languages.
Apex Learning is a private online school with high school summer courses, including college prep, world language, core, elective and career prep courses.