Spain left London with a total of 17 Olympic medals (3 gold, 10 silver, and 4 bronze), failing a single medal short of the total achieved in Beijing. Three of these medals were awarded to the team in taekwondo and canoeing, and two each in sailing, swimming, and synchronized swimming. Three Spanish athletes won more than a single medal in London, while all of their competitors in synchronized swimming and taekwondo won at least one medal. Spain's team-based athletes also proved successful in London, as the women's handball and water polo teams won silver and bronze medals, respectively. The men's basketball team managed to repeat its silver medal from Beijing. At these Olympic games, Spain, however, did not win an Olympic medal in tennis, for the first time since it was reintroduced as a full-medal sport in 1988, and in cycling for the first time since that same year. On 21 November 2016, a fourth gold medal was assigned to Spain's Lidia Valentín in Weightlifting (Women's 75 kg) after the IOC disqualified the original medalists in the event for failing doping tests at the games.
Among the nation's medalists were sailor Marina Alabau in women's windsurfing, and sprint kayaker Saúl Craviotto, who previously won gold in Beijing. Three athletes won Spain's first ever Olympic medals in their respective disciplines: triathlete Javier Gómez Noya, slalom kayaker Maialen Chourraut, and freestyle wrestler Maider Unda. Sprint canoer David Cal, who won silver in London, became the first Spanish athlete in history to win a total of five Olympic medals. Meanwhile, Mireia Belmonte became the first Spanish swimmer in history to win two Olympic medals.
The Spanish Olympic Committee (Spanish: Comité Olímpico Español, COE) selected a team of 278 athletes, 166 men and 112 women, to compete in 23 sports; it was the nation's sixth-largest team sent to the Olympics, but the smallest since 1988. Spain did not qualify athletes in fencing, modern pentathlon, and rowing, but there was only a single competitor in women's freestyle wrestling. Athletics was the largest team by sport, with a total of 46 competitors.
The Spanish team featured several Olympic medalists from Beijing, including sailors Iker Martínez and Xabier Fernández in the open skiff class, and sprint canoer David Cal, who won the silver in two of his events. Race walker Jesús Ángel García became the second Spanish athlete to compete in six Olympic games, tying the record set by former water polo player Manuel Estiarte. Meanwhile, another race walker María Vasco, and field hockey player Pablo Amat competed at their fifth Olympics. Table tennis player He Zhi Wen, at age 50, was the oldest athlete of the team, while rhythmic gymnast Lourdes Mohedano was the youngest at age 17.
Other notable Spanish athletes featured sprint kayaker and two-time world champion Saúl Craviotto, swimmer Mireia Belmonte García in the women's medley, butterfly, and freestyle events, tennis doubles specialist Anabel Medina Garrigues, and NBA basketball players Victor Claver and Serge Ibaka. Former world number-one male tennis player and defending Olympic champion Rafael Nadal was initially selected by the committee to carry the nation's flag, but he later withdrew from the Games because of an undisclosed injury. On 20 July 2012, NBA basketball star Pau Gasol, who led his team by winning the silver medal in Beijing, replaced Nadal as Spain's flag bearer at the opening ceremony.
The following is the list of number of competitors participating in the Games. Note that reserves for fencing, field hockey, football, and handball are not counted as athletes:
Spanish swimmers achieved qualifying standards in the following events (up to a maximum of 2 swimmers in each event at the Olympic Qualifying Time (OQT), and 1 at the Olympic Selection Time (OST)):
As Spain was suffering from the 2008–2014 financial crisis, the Spanish Olympic team saved EUR1.5 million by obtaining free uniforms for the opening ceremony from the Russian sportswear company Bosco, which was a team sponsor and also provided the Russian and Ukrainian teams' outfits. Spanish athletes criticized the outfits' appearance as "loud, very loud", however, saying that "there aren't enough adjectives".The Moscow Times described the uniforms' colors as "a never-before-seen mix of cherry red, orange and canary yellow", and NPR stated that the outfits appeared designed for Ronald McDonald.