[7] Renovations and additions begun in 2006 and completed at end of the 2008–09 school year included a new gym, more parking spaces, a new cover for the pool, more classrooms, improvements on the HVAC system, and artificial turf for the football field.

The school was ranked 132nd in the nation and seventh in New Jersey on the list of "America's Best High Schools 2012" prepared by The Daily Beast / Newsweek, with rankings based primarily on graduation rate, matriculation rate for college and number of Advanced Placement / International Baccalaureate courses taken per student, with lesser factors based on average scores on the SAT / ACT, average AP/IB scores and the number of AP/IB courses available to students.

[24] The school newspaper is called The Pirate's Eye, which won the Columbia Scholastic Press Association Gold Medal in both 2007 and 2008.

The West Windsor-Plainsboro High School South Pirates[3] compete in the Colonial Valley Conference, which is comprised high schools from Mercer, Middlesex and Monmouth counties, operating under the supervision of the New Jersey State Interscholastic Athletic Association (NJSIAA).

[26] After High School North suspended its football program, the district received approval from the NJSIAA to establish a co-operative North / South football team named "WW-P United" starting in the 2018–19 school year.

From 1973 to 2003, the Pirate football team bore a "Golden Dome," or a yellow helmet, which for much of that time was blank without a decal.

Some of South's historically dominant athletic teams include both Boys' and Girls' swimming and diving, tennis, golf, basketball, fencing and lacrosse.

These co-op programs operate under agreements scheduled to expire at the end of the 2023–24 school year.

Given that the size of the schools is larger than the threshold established by the state for co-op programs (North is classified as Group III and South as Group IV, based on the size of the enrollment of each school), the proposal was rejected by the West Jersey Football League and by the Leagues and Conferences Committee of the New Jersey State Interscholastic Athletic Association, before an appeal of the decision was rejected by the Commissioner of the New Jersey Department of Education.

The 2007 boys' tennis team won the Central, Group IV state sectional championship with a 4–1 win against East Brunswick High School.

The South Varsity Boys' tennis squad was ranked #2 in the state for five consecutive years during this span.

During this period, the team captured five consecutive Central New Jersey Group IV state titles, five consecutive Group IV state titles, and an unprecedented sweep, in which they did not lose one single match, of the Mercer County Tournament four years in a row.

These two historically bitter rivals battled for the title of dominating team in Mercer County and placed their respective state rankings of #2 and #4 on the line.

[citation needed] At the end of the day, the South team prevailed with a victory of 186-187 that came down to the last putt of the last player of the last group.

The Pirates put an end to the Tigers previous three-year unbeaten record in Mercer County matches.

[38] The girls' swim team won the Central - A state sectional championship in 2007 with a 97–73 win over Montgomery High School.

In the 2008–09 season saw an undefeated CVC season, and MCT first place, a sectional championship, and finally the state title, winning the Public A state championship against the top seeded Westfield High School Blue Devils with a score of 90–80.

[40] Both the girls' and boys' swim teams were the Colonial Valley Conference Champions for the 2007–08 season.

[41] The girls tennis team won the Group IV state championship in 2014, defeating Ridge High School 3–2 in the tournament final.

[45] South's Brian Leung was the 2007 New Jersey Cross-Country Champion and the team finished 7th in the state, the program's best season to date.

They won the Mercer County Championship (snapping rival WW-P North's four-year winning streak), won the Central Jersey Group IV title, finished second in Group IV, and a strong 3rd place at the state meet, before finishing 5th at the Nike Northeast Regional.

[48] The West Windsor-Plainsboro High School South Model United Nations program dates back to the late 1970s and consists of approximately 40 students.

Typically, the mocks involve more than 100 students vying for a limited number of conference spots, with roster decisions being made by the elected officers.

In 2014, SouthMUN performed very similarly to the 2011 season, winning delegation awards at 4 out of 5 of the conferences attended, winning Best Small at William and Mary High School Model United Nations (WMHSMUN), Best Large at PMUNC, Best Large at Washington Area Model United Nations Conference (WAMUNC) and Best Small at CMUNC.

[52] In 2014, South won the State Tournament for the 6th year in a row and went on to finish in the top ten at Nationals.

The team placed 20th overall and won medals in Disease Detectives (6th), Materials Science (6th), Microbe Mission (5th), and Optics (6th).

[56] In 2010, the team secured a first-place finish at the regional tournament held in the Princeton Plasma Physics Laboratory.