Taking the example of vibrational-assisted concerted proton exchange in cyclic (HF)(n) (n = 4, 5) oligomers, we demonstrate that proton transfer occurs in three different ways, depending on the temperature. At high temperatures (>400 K) mainly overbarrier transitions take place. To predict the reaction rate, the barrier height needs to be known, at least at chemical accuracy. At intermediate temperatures (200-400 K) additionally an accurate knowledge of the barrier width is important, as the protons mainly tunnel through the barrier near its top. The adiabatic tunneling correction can be used to predict reaction dynamics, as the vibrational state does not change during the reaction. At low temperatures (<200 K) the slow skeletal modes are frozen and only fast hydrogenic movement takes place. For this reason vibrational adiabaticity is lost and a much wider region of the potential surface called reaction swath is crossed during the reaction. predictions of the resulting exchange dynamics require the potential on the swath to be calculated accurately. In the zero-temperature limit these nonadiabatic tunneling paths solely determine the exchange reaction and cause spectroscopically measurable tunneling splittings, which can, therefore, be estimated reliably in the framework of transition-state theory from accurate calculations of energies on the reaction swath. All the above findings arise just from the fact that a light atom is transferred between two heavy atoms. Therefore, two crossover temperatures of proton transfer should qualitatively exist in all systems containing hydrogen bonds.