In 2015, Varinska competed in the European Youth Olympic Festival. She scored a 53.050 all-around in qualifications, which qualified her to the all-around final, and the uneven bars final. In the all-around, she scored a 51.100, placing 17th. In the uneven bars final, she came 4th, scoring 14.650: a significant improvement on her qualifying bars score of 14.100 and 2.5 points higher than her all-around bars score of 12.150. 2016 brought three international competitions for Varinska. In February, she "swept" the junior division of the Antonia Koshel Cup competition, held in Minsk, Belarus. Varinska placed first on every apparatus, and also in the all-around. In June, Varinska competed at the 2016 European Women's Artistic Gymnastics Championships, held in Bern, Switzerland. She placed 30th in the all-around competition, with a score of 50.099. She achieved a 13.900 on vault, 11.200 on the uneven bars, 12.366 on the balance beam, and 12.633 on the floor exercise. Varinska did not qualify into any finals. She contributed to the Ukrainian team's 152.787 points, to achieve an 11th-place finish in the team qualification. Varinska's final international outing in 2016 saw her compete only uneven bars, balance beam, and floor exercise. She competed at the Belarusian Championships, where she qualified for all three finals. She did not, however, compete in those finals as both Diana and her teammate, Angelina Kysla, were unranked during the qualifications, due to not being Belarusian.
Senior career
Varinska turned 16 in 2017, which qualified her to compete in the senior division of competitions. She began her senior career at the Baku World Cup. She competed only on the uneven bars, qualifying in first place to the final. In the finals, she took the gold medal with a 13.933. The 2017 European Gymnastics Championships saw Varinska compete only on the uneven bars in qualification. She scored a disappointing 12.766 and failed to qualify into the final. In May, Varinska competed in the Osijek Challenge Cup, held in Osijek, Croatia. She competed on the uneven bars, beam, and floor exercise in qualifications. She qualified into the beam and floor finals, but did not place, coming in 7th on beam and 4th on floor. In June, a video of Varinska's bars routine at the Ukraine Cup, an internal Ukrainian competition, emerged online. Fans were excited by its difficulty and good execution, but noted Varinska's tendency to falter in competition did not guarantee her success on the world stage at the World Championships, to be held in Montreal, Canada. However, she still competed well at these championships, Qualifying to the Uneven Bars final and placing sixth with a clean routine. She hit all of her bar routines throughout the competition.
