A system and method for providing a bi-directional, valve-less sampling port for use with gas sampling bags, wherein the valve-less sampling port has few parts and no moving parts, the sampling port is coupled to a gas sampling bag using a base component that has a portion inside and outside of the gas sampling bag, a cap that is disposed over the base to make an interference fit, an O-ring between the base and the cap that applies a sealing force to hold the gas sampling bag against the base, and a dome seal inside the base and held in place by the cap, wherein the dome seal functions as a one-way check valve to prevent flow out of the gas sampling bag until a sampling adapter is inserted through the cap and the dome seal to provide access to the gas sampling bag for extraction of gas.