Team Qualifications
Can you jump? Can you dig? Can you pass? Can you block? Can you spike? Do you communicate well? If your answer to any one of those questions is "no," then you might want to consider a different sport.
In indoor volleyball, individual positions are an essential part of the game. With six people on the floor per team at any given time, each player has a specific role: setter, middle hitter, defensive specialist, and so on.
In sand volleyball, however, you have to be an all-around player. Generally, one partner will still be taller than the other (for example, Kerri Walsh-Jennings is 6'2" and Misty May-Treanor is 5'9"). The taller person plays closer to the net. So Walsh-Jennings plays the "blocker" position and May-Treanor plays the role of "defender" (source). Every duo's gotta have a Walsh-Jennings and a May-Treanor.
A typical ten-athlete roster is comprised of five partner pairs, and these teams are numbered one through five. Each team competes in a match against the equivalent pair of the opposing school. The NCAA tracks each duo's win/loss record to determine who qualifies for the pairs' championships in May (source).
Every school has a slightly different academic standard for athletes. It's the athletes' job to take the proper number of classes and maintain the minimum GPA of 2.0.
Anyone who meets the D-I minimums would also be eligible for D-II. NAIA programs have even lower NCAA-mandated standards. However, given sand volleyball's status as an emerging sport, there aren't many programs below the D-I level at this time. There are only four D-II schools with varsity sand programs currently approved by the NCAA, and only four approved NAIA programs. Sand volleyball is a growing sport amongst junior colleges, though, featuring 24 established programs as of the 2014–2015 season, with 17 more on the way for 2015–2016 (source).