Bay Area Regional Science Olympiad has the following 2 Divisions:
Division B (Grades 6-9)
Division C (Grades 9-12)

Students on the team must be from the membership school; and a school is considered to be a separate school if it has a separate administrator. Recruiting from neighboring schools, districts, counties or states is not permitted. Any student can compete at only one Division level (either Division B or C, not both) at a single school.

Division C Team Membership Rules
A team may have up to fifteen (15) members. A maximum of seven (7) 12th grade students is permitted on a Division C team.

Division B Team Membership Rules 
A team may have up to fifteen (15) members. A maximum of five (5) 9th grade students is permitted on a Division B team. Because middle schools that do not have grades 7, 8 or 9 are at a slight disadvantage, they may invite any combination of up to five (5) of their last year's 6th, 7th or 8th grade students to be part of the team. Possible examples/scenarios:

A school with grades X-9 can only have 5 students from grade 9 (in their current enrollment)
A school with grades X-8 can only bring back 5 students from grade 9 (from the previous year's enrollment of 8th grade students)
A school with grades X-7 can only bring back 5 students from grade 8 or 9 (who had been previously enrolled in that school as a 7th grade student)
A school with grades X-6 can only bring back 5 students from grades 7, 8 or 9 (who had been previously enrolled in that school as a 6th grader)

Student Below Grade Level Designations
Science Olympiad encourages students to participate in the Division that matches current Science Olympiad grade level designations. However, to support the inclusion of students who wish to participate in Science Olympiad, schools with grade levels lower than those stated in a Division are permitted to invite members below the grade level designations. (A K-8 school could enlist a Division B team of all 5th graders) Participation is limited to age-appropriate events (as determined by a coach, principal or tournament director) and prohibited where safety is a concern (such as the use of chemicals).

Public School Students
It is recommended that all public school students may participate in Science Olympiad only as members of a team that is formed in the local public school that they attend. However, very small schools in the same state may combine students to form one team if and only if the total enrollment of the combined schools is less than 300 students. This policy only applies to public schools.

Private, Charter and Alternative School Students
Private schools, “governor” schools, charter schools, and any other school that is qualified by the state and is housed in a single geographic location, may form Science Olympiad teams from among the students in their student body, regardless of where that student's home of origin is located. Such schools may not solicit or enlist public school or home-schooled students on their teams.

Home-Schooled Students
Option 1 - Participation through a Local Public SchoolIf the state in which a home schooled student resides allows home schooled students to participate in public school activities, home schooled students may either (1) choose to participate as a member of the Science Olympiad team at the local public school they would attend were they not home schooled, or (2) form a home school team as set forth in Option #2, below.

Option 2 - Participation through a Home School TeamScience Olympiad will recognize Home School Teams consisting only of students who live within the boundaries of two contiguous (side-by-side) geographic counties in a single state.

Cyber or Virtual School (Online) Students
Option 1 - Participation through a Local Public SchoolIf the state in which a cyber/virtual school student resides allows cyber/virtual school students to participate in local public school activities, cyber/virtual school students may either (1) choose to participate as a member of the Science Olympiad team at the local public school they would attend were they not enrolled in the cyber/virtual school, or (2) form a cyber/virtual school team from among the students in that school's student body as if they were students in a private/charter school as set forth above. A student may only participate on a single team.

Option 2 - Participation solely through a State-Recognized Cyber or Virtual SchoolIf the state in which a cyber/virtual school student resides recognizes and financially supports cyber/virtual schools, Science Olympiad will also recognize cyber/virtual school teams consisting only of students who are enrolled at that cyber/virtual school. Such schools may not solicit or enlist public school, private school or home-schooled students on their teams.