Larkins played for The Benjamin School in North Palm Beach, Florida, where she was named a WBCA All-American. She participated in the 2004 WBCA High School All-America Game where she scored four points. She is the school's all-time leading scorer with over 3,000 career points.
Larkins was a member of the USA Women's U18 team which won the gold medal at the FIBA Americas Championship in Mayaguez, Puerto Rico. The event was held in August 2004, when the USA team defeated Puerto Rico to win the championship. Larkins helped the team win the gold medal, scoring 9.0 points per game and recording eleven steals during the event.
She continued on as the U18 team became the USA Women's U19 team which competed in the 2005 U19 World Championships in Tunis, Tunisia. The USA team won all eight games, winning the gold medal. Larkins hit eight out of nine field goals attempts in the opening round game against South Korea. In the gold medal game, she was a perfect nine for nine, scoring 20 points.
Larkins played for the USA team in the 2007 Pan American Games in Rio de Janeiro, Brazil. The team won all five games, earning the Gold Medal for the event.
Larkins played college basketball at the University of North Carolina for the Tar Heels. She made the all-ACC first team in 2006, 2007, and 2008.
Larkins was drafted 14th overall by the New York Liberty in the 2008 WNBA Draft. In her rookie season, she averaged 4.8 ppg and 2.7 rpg off the bench. In 2010, Larkins was waived by the Liberty. During her three-year absence from the WNBA she played overseas in Turkey for Mersin Büyükşehir Belediyesi. In 2011, Larkins had signed a training camp contract with the Phoenix Mercury but was waived before the start of the season.
In 2012, Larkins signed with the Indiana Fever. In her first season with the Fever, she averaged 4.1 ppg and 4.4 rpg as a reserve. The Fever finished second place in the Eastern Conference with a 22-12 record. During the playoffs, Larkins was put in the starting lineup at the four spot and was effective for the Fever with her scoring and rebounding, nearly averaging a double-double (9.9 ppg and 10.9 rpg). The Fever would eventually end up winning the 2012 WNBA Championship after they defeated the Minnesota Lynx 3-1 in the Finals. During the series, Larkins had tied the second-most total for rebounds in a WNBA Finals game when she grabbed 15 rebounds in Game 1.
The following season, Larkins became the starting power forward for the Fever and averaged 7.9 ppg as well as 7.8 rpg. In 2014, Larkins re-signed with the Fever. During the 2014 season, Larkins put up career-best averages of 9.7 ppg and 9.2 rpg (ranked fourth in the league). She had also led the league in field goal percentage, shooting 59%.
In the 2015 season, Larkins missed several games due to a knee injury and played 21 games with only 3 starts, but was able to start again for the Fever during the playoffs. The Fever had advanced all the way to the Finals for a rematch with the Lynx but lost the series 3-2.
In the 2016 season, Larkins was healthy again after undergoing surgery on her knee. She started in 33 games, averaging 8.3 ppg and 7.4 rpg. She also achieved a career-high in field goal percentage, shooting 63% which was ranked second in the league. The Fever made it to the playoffs, but were eliminated in the first round elimination game by the Phoenix Mercury.
In 2017, Larkins re-signed with the Fever once again in free agency. During the 2017 season, Larkins would start in 17 of the 34 games played, having her role reduced from the starting center and have her minutes cut. The Fever would finish with a dissapointing 9-25 record and 11th place in the league.
In the 2008-09 WNBA off-season, Larkins played in Turkey for Samsun B.K.. From 2009 to 2013, Larkins played four off-seasons for Mersin Büyükşehir Belediyesi. In the first portion of the 2013-14 WNBA off-season, Larkins played in China for the Jiangsu Phoenix and played the rest of the off-season in Italy for Famila Schio. In the 2014-15 WNBA off-season, Larkins played in Turkey for Adana ASKİ SK.