Thomas Allen Shields (born July 11, 1991) is an American swimmer who swims for the University of California, Berkeley. In 2016, Shields placed second in the 200 m butterfly at the US Olympic Swimming Trials. He currently holds the short-course American records in the 50-meter, 100-meter, and 200-meter butterfly events, as well as the 100-yard butterfly.
At the 2011 NCAA Division 1 Championships, Shields won the 100-yard backstroke (45.02), second place in the 100-yard butterfly (44.91), and third in the 200-yard butterfly (1:41.20). He anchored the second place 4×50-yard freestyle relay, the 4×100-yard freestyle relay, and 4×200-yard freestyle relay. He swam the butterfly leg for the medley relays.
Shields swam for Cal at the 2012 NCAA Swimming Championships. Shields finished first in the 100-yard Butterfly (44.76) and the 100-yard backstroke (44.86). He finished second to teammate Will Hamilton in the 200-yard Butterfly (1:41.07). He anchored the 400-yard Freestyle relay with a split of 41.79, and started the 800 Freestyle Relay (splitting a 1:33.72). He swam the butterfly leg in both the 200-yard Medley Relay (19.80 split) and the first-place finishing 400 Medley Relay (splitting a 43.56).
He concluded his collegiate career with two first-place finishes in the 100 fly (44.59) and the 200 fly (1:39.65) and a second-place finish in the 100 back (45.21) at the 2013 NCAA D1 Championships. Shields's 200 fly time tied Michael Phelps for the fastest short course time in history. The University of California, Berkeley, finished second in the meet to the University of Michigan.
At the 2011 Summer Universiade in Shenzhen, Shields earned the first international medal of his career, a gold, in the 4×200-meter freestyle relay for his contribution in the heats. As the second leg, Shields had a split of 1:50.57. Shields earned his first individual medal, a silver, in the 100-meter butterfly, finishing behind compatriot Tim Phillips. Shields also earned a silver medal in the 4×100-meter medley relay for his contribution in the heats.
At the 2012 U.S. Olympic Team Trials, Shields finished fourth place in the 100-meter butterfly behind Michael Phelps, Tyler McGill, and Ryan Lochte, with a time of 51.86. He finished ninth place in the 200-meter butterfly semi-finals with a time of 1:58.75. Additionally, he competed in the 100-meter freestyle, finishing twenty-first in the heats (49.96).