Country: United States

Breakout soccer star Alex Morgan came off the bench during the 2011 Women’s World Cup to become a top goal scorer for Team U.S.A. She was one of two U.S. players to score in both the World Cup semifinal and championship game. Her team ultimately lost the Cup to Japan on penalty kicks. The speedy striker became a full-time starter for the U.S. earlier this year, and her game has only improved. In 2012, Morgan has scored 17 goals in 15 games. She has been eating healthier and more closely analyzing her game to prepare for her Olympic debut this summer. “I want to make a bigger impact on this team’s success,” Morgan told TIME. At the London Games, the U.S. women’s team will be defending their two-time Olympic gold winning streak from the 2004 and 2008 Games.

Country: Qatar

Bahiya Al-Hamad is already making history as she enters this year’s Olympic games. The air-rifle shooter is one of three female athletes from Qatar competing in London.  This will be the first time in history that the small nation sends females to take part in the Olympic games. For Al-Hamad, the possibility of earning a medal is much more than a personal victory. “It’s an accomplishment for every Qatari woman,” she told CNN. “I hope I can live up to their expectation.”

Country: United States

Sprinter Carmelita Jeter has been picking up speed since failing to qualify for the 2008 Olympic Games. After her setback, she switched coaches and increased her training schedule. “She didn’t have success early,” her coach, John Smith, told Sports Illustrated. “That’s made her very hungry. The lady will run through a brick wall for me.” During one week in September 2009, Jeter ran the 100-meter in 10.64 seconds and 10.67 seconds. Those are two of the six fastest 100-meter sprints of all time by a woman (the world record in 10.49). More recently, at the 2011 World Outdoor Championships, Jeter won the 100-meter, finished second in the 200-meter and earned a gold medal with Team U.S.A. in the 4x100 relay. She will be racing for the gold in the 100-meter and 200-meter events at the London Games.

Country: Mexico

Carolina Mendoza, the 10-meter platform diver from Mexico, is one of the youngest athletes ever to qualify for the Olympic games. The teen qualified in February when she was just 14. Mendoza finished fifth in this year’s World Championships and will be the youngest competitor in the 10-meter event in the Olympics. Her coach describes the young teen as ”fearless” and there is a good chance she will bring home Mexico’s first individual women’s Olympic diving medal.

Country: United States

BMX rider Connor Fields is making his Olympic debut after winning the 2012 U.S. Olympic Trials for BMX cycling, the newest sport at the London Games (BMX first appeared at the 2008 Games). Fields, who has been riding since he was seven years old, is one of the sport’s top athletes. This season, he became the first to win three straight Supercross World Cup finals. In 2011, he also won gold at the Pan American Games. Fields says it’s the thrill of the unknown that draws him to the sport. “I love the feeling right before you start a race,” he told TFK. “You have no idea what’s going to happen or what you will do, and you have an adrenaline rush and butterflies. That’s what I enjoy.”

Country: United States

Because of her gravity-defying moves, Gabrielle Douglas is known as the “Flying Squirrel.” She is the second African American ever to hold a spot on the U.S. women’s gymnastics team. Douglas earned that spot when she won the Olympic trials by one-tenth of a point over world champion Jordyn Wieber. (Wieber is also part of Team U.S.A.) This summer, Douglas hopes to help bring U.S. gymnastics its first team gold since 1996.

Country: United States

Holley Mangold has been a competitive weight lifter for only 3 ½ years. But she’s always been strong—strong enough to play football in high school as reserve offensive lineman (she’s also the younger sister of New York Jets Pro Bowl center Nick Mangold). Mangold was the first girl in Ohio to play a down from the line of scrimmage in a varsity football game. She was also the first to play in a state championship game. Mangold got her lifting start as a power lifter, before switching to Olympic weight lifting with the far-reaching goal of making it to the 2012 London Games. She succeeded; Mangold will make her Olympic debut in the super-heavyweight division this summer.

Country: Australia

You may not have heard of James Magnussen, but you will soon. The Summer Games will be Magnussen’s first Olympics, but that doesn’t mean he’s inexperienced. The Australian swimmer is the current world champion for the 100-meter freestyle competition, which he swam in 47.10 seconds at the Australian Olympic Trials. In the London Olympics, Magnussen will compete in the 50-meter freestyle, the 100-meter freestyle and the 400-meter freestyle relay. Magnussen is Australia’s top chance at a gold medal.  Many see Magnussen as the man most likely to take down American ace Michael Phelps in the 100-meter freestyle. “If you want to be the best, you have to beat the best,” he says.

Country: United States

Jordyn Wieber, a Michigan native, is the current world all-around champion. Even though she was defeated at the Olympic trials by a tenth of a point by Gabrielle Douglas, Wieber is still a London-bound favorite. Having trained as a gymnast since the age of four, Wieber is an all-around gymnast, which means that she can compete in all four events: vault, uneven bars, balance beam and floor.

Country: Republic of Ireland

This year will mark the first time women’s boxing becomes an Olympic event. A major reason for this is due to the efforts and success of Katie Taylor. The athlete began training as a child with her father—a former heavyweight-boxing champ. Since winning her first world title in 2006, Taylor has won many international competitions. Taylor is the top female lightweight in this year’s Olympics and is favored to win the gold medal.

Country: United States

Kayla Harrison (in blue, above), a two-time national champion in Judo before she turned 18, won the U.S. Olympic Team Trials in 2008. But she didn’t get to compete in the Games because Team USA did not qualify in the division. Still, Harrison stayed dedicated to the sport. In 2010, she became the first U.S. woman to win a world championship in 26 years. She followed that with another gold at the 2011 Pan-American Judo Championships. This summer, Harrison will finally have her chance at Olympic gold. A win would make her the U.S.’s first Olympic judo champion. “If you want to be the best at something, it takes hard work, dedication, sacrifice and perseverance,” Harrison told TFK. “There is no secret formula, except for that.”

Country: United States

Just a few weeks after playing in the NBA Finals for the Oklahoma City Thunder, Kevin Durant is back on the basketball court, this time looking for his first Olympic Gold medal.  Durant has led the NBA in scoring three times. In 2009-10 he became the youngest NBA player to win a scoring title. This will be Durant’s first Olympics, but his second time representing Team USA on a big stage. In 2010, he set a U.S. record for most points in a world-championship tournament with 38 in a semifinal against Lithuania.  The United States is heavily favored to win gold this year with a team that includes returning gold medalists Kobe Bryant and LeBron James.

Country: Romania

This Romanian gymnast began training when she was 4 years old. Ten years later, she was nicknamed the “New Nadia”, after Nadia Comanci, the first female gymnast to score a perfect 10 at the Olympics. This March at the American Cup, Iordache’s first international competition, she placed third in the all-around. Then in May, she helped Romania win a team gold at the Euro Championships. Her tumbling skills make her one to watch this summer in London.

Country: Russia

When Maria Sharapova won the Wimbledon tournament at 17, she became the woman to beat. But in 2008, shoulder surgery sidelined the tennis prodigy and nearly sent her into early retirement. Her rank fell to Number 126 and critics thought she might never make a comeback. This year, she proved them wrong. On June 9, Sharapova won the French Open singles final and for a short time, re-claimed the Number 1. And she received more good news. During the third round of the competition, Sharapova was asked to be Russia’s first woman to carry the Russian flag at the opening ceremony. “I am so honored, and especially excited as it will be my first Olympics in my career,” she says on her official website. As for the matches themselves, Sharapova will have to bring her A-game to beat the best women in the world, including the new Number 1 player, Victoria Azarenka.

Country: Great Britain

Mark Cavendish claims he is the  “fastest man on two wheels.“  The Brit will compete in the very first event of the 2012 Olympic games: the men’s road race. Last year, Cavendish became the road world champion and was Great Britain’s first cycling winner in 46 years. The speedy rider is confident that he will remain the ”fastest man on two wheels” and will win the gold in London.

Country: United States

Maya Moore already has an impressive list of accomplishments: WNBA and NCAA champion, WNBA All-Star, and college All-America.  An Olympic Gold Medal would be one more achievement to add to her résumé. Moore will be part of a powerful United States squad that won the world championship in 2010 and is the heavy favorite to win gold in London. The U.S. women’s national team has won gold in four straight Olympics.

Country: Brunei

The country of Brunei has only participated in the Olympics three times: 1996, 2000 and 2004. Each of those times, the country sent one athlete—a male—to the Games. This summer, for the first time, Brunei is sending a woman. Maziah Mahusin will compete in the women’s 400-meter sprinting event. Even though she has not met the qualifying time, she will be allowed to participate thanks to the “concept of universality.” This rule makes it possible for countries to enter unqualified athletes in sports if they do not have athletes who qualify. “I am working on improving my time to one that my coach and I can be proud of,” Mahusin told TIME. 

Country: United States

None other than Michael Phelps calls Missy Franklin, 17, one of the best female swimmers he’s ever seen. A talented backstroker and freestyle swimmer, she collected three gold medals at the 2011 World Championships. It’s no surprise that the Olympic newcomer qualified to swim in four individual events and two relays in London. In doing so, Franklin will become the first American female to swim seven events at the Olympics. She's the defending world champion of the 200-meter backstroke and heads to London as the overwhelming favorite in that race.

But it’s more than her talent that’s making “Missy the Missile” a favorite among fans. Franklin is all smiles before and after she races. She says she even smiles as she races. Veteran teammate Natalie Coughlin thinks her pep will help. “There is just a wonder, freshness and naivety that helps manage all the expectations and all the pressures,” Coughlin says. Franklin says it’s the support of her family and friends that help the most. "No matter what happens, I know I get to go home to them," she says.

Country: South Africa

When Pistorius runs the 400-meter and the 4x400-meter relay in London, he will become the first double amputee to compete at the Olympics.  Pistorius has lived nearly his entire life without the bottom halves of his legs. He uses prosthetic legs to run and walk. Pistorius won gold medals at the Athens and Beijing Paralympics, but this will be his first run in an able-bodied Olympics. “To have been selected to represent Team South Africa at the London 2012 Olympic Games in the individual 400m and the 4x400m relay is a real honor,” Pistorius said in a statement. “I am so pleased that years of hard work, determination, and sacrifice have all come together.”

Country: Jamaica

Yohan Blake is the reigning world champion in the 100-meter sprint.  But some people think that he only won because his teammate, Usain Bolt, was disqualified for a false start.  “I understand why people say that,” Blake told TIME. “Bolt is the king of track and field.”  Blake and Bolt are appropriate rivals. Both grew up in the poor Jamaican countryside and both rose above poverty with their sprinting careers. Now they both will be facing each other in the Olympics  — but only one can win gold. “We’re hungry for something,” Blake says. “We want it so bad.”

Click here to view a slide show of Olympians returning to the Games in 2012.