This paper presents a hybrid dual-path Buck-Boost DC-DC converter (DPBB) achieving high power efficiency for the entire input voltage (VIN) range (2.8 to 4.2V) from a Li-ion battery for mobile applications. Unlike conventional noninverting buck-boost converters (CBB), the proposed DPBB supplies a load current (ILOAD) at all phases by using the inductor path (L-path) and capacitor path (C-path) alternately. As a result, our design achieves high efficiency by reducing conduction losses and suppresses the output voltage (VOUT) ripple. It has only a single control mode over the whole VIN range, unlike the previous designs that require complex mode transitions. Note that high efficiency is achieved not only across a wide ILOAD range but also over a wide VIN range. The proposed DPBB achieves 96.6% peak efficiency with the smallest difference between the maximum and minimum efficiencies over a given range of ILOAD and VIN.