Claudia Anne Kolb (born December 19, 1949) is an American former competition swimmer, two-time Olympic champion, and former world record-holder in four events.
Kolb, who swam with the Santa Clara Swim Club and was coached by George Haines, first burst into prominence in 1964, as a 14-year-old, by winning the Amateur Athletic Union (AAU) outdoor 100- and 200-meter breaststroke championships and the indoor 100-yard breaststroke title. She repeated in both AAU outdoor breaststroke championships in 1965, when she also won the 200-meter individual medley.
Kolb represented the United States at the 1964 Summer Olympics in Tokyo, Japan. She competed in the women's 200-meter breaststroke, and received the silver medal for her second-place performance (2:47.6) behind Soviet Galina Prozumenshchikova, who set a new Olympic record (2:46.4).
Although she had set a world record of 1:17.9 in the 100-meter breaststroke in 1964 and won a surprising silver medal in the 200-meter event at the 1964 Olympics, she decided to concentrate on the individual medley races in 1966. Going into the 1968 Olympics, Kolb held world records of 2:23.5 in the 200-meter individual medley and 5:04.7 in the 400-meter.
When Mexico City hosted the 1968 Summer Olympics, Kolb won two gold medals. She dominated her competition in the medley events, winning both the 200-meter individual medley (2:24.7) and 400-meter individual medley (5:08.5). Kolb set new Olympic records in both events in the preliminary heats and the event finals. Her 20-meter margin in the 400-meter event was the most decisive Olympic victory by a woman swimmer since 1928.
Kolb retired from competition swimming after the Mexico Olympics. Her married name is Claudia Thomas. She has coached swimming at clubs in South Bend, Indiana and Santa Clara, California, and college teams at Stanford University and at Pacific University. Her Stanford swimmers won the 1980 AIAW national team championship.
She currently lives in Oregon.