As wind turbines increase in size to meet future energy demands, their larger size and head-to-mass ratio result in lower tower’s natural frequencies and the lower critical velocity of Vortex-Induced Vibrations (VIV). Consequently, VIV in the first mode is expected to occur more frequently at lower wind speeds, while second mode VIV can occur at moderate to high wind speeds. A full-scale measurement campaign was conducted on two wind turbine towers in Østerild, Denmark, from July 2021 to early 2024. VIV occurrences were measured on the towers both for tower-only and fully-built configurations. Interestingly, the 2nd mode VIV on a fully-built wind turbine was indeed measured. This paper presents insights and valuable data set of field-measured 2nd mode VIV event. The effect of coexisting 1st mode oscillation at tower top and high gust fluctuations reflected in the response signal are discussed.