Tellgren finished eighth overall in the the 1-meter diving at the 2013 NCAA Swimming and Diving Championships on Thursday evening, with a score of 437.35. The top eight finishers lock up an All-American honors. He becomes RIT's sixth diver to earn All-American honors. On Saturday, Tellgren was named an honorable mention All-American by placing 15th in the 3-meter event with a score of 449.40. Tellgren posted a preliminary score of 455.30 to move into the championship finals. Ben Lewis of Denison took home first place with a final score of 494.65. Tellgren joins Gregg Sheibley (1987, 1988), Ryan Schaefer (2004, 2005) Matt Joseph (2005, 2006, 2007, 2008), Matt Joseph (2007, 2008), and Evan Wendt (2011) as All-American divers at RIT. On Saturday, Tellgren recorded a score of 458.70 in the prelims of the 3-meter diving championship, which was 14th best in the competition. In the finals, his score of 449.40 was good for 15th overall.