Kosigina began skating with Nikolai Moroshkin in June 2010, coached by Alexei Gorshkov in Kosigina's hometown of Odintsovo, near Moscow. During the 2010–11 season, Kosigina/Moroshkin won bronze at their first JGP event, in Courchevel, France. At their second event, in Dresden, Germany, they won a gold medal. These medals qualified them for the Junior Grand Prix Final, where they finished sixth. At the 2011 Russian Junior Championships, Kosigina/Moroshkin won the bronze medal and then placed sixth at the 2011 World Junior Championships.