We study the quantum exciton dynamics in light‐harvesting complexes under the influence of underdamped vibrational molecular modes. We observe prolonged coherent population oscillations between different pigments due to an underdamped mode connected to the originally excited pigment. At the same time, an underdamped vibration at the exit site of the complex provides additional channels for the excitation energy transfer towards the reaction center which shortens the transfer times. image