Abstract: Devices, kits, and methods for selectively and alternately isolating one of a pair of bronchi or lungs are provided. A main body has proximal and distal ends defining a lumen, and a side port and opening formed near the distal end. An insert having first and second ends, and an aperture located at or near the second end, is configured to have the second end placed in the main body lumen. The insert aperture permits passageway to at least one of the main body side port or distal opening, while an exchangeable insert permits passageway to the other main body side port or opening, or optionally one insert may move between first and second positions to selectively and alternately permit passageway to the one or other main body side port or opening. Also provided are kits and methods of using lung isolating devices as taught herein for selectively and alternately isolating one of a pair of bronchi or lungs.