An inflatable seat belt system comprising: a shoulder belt member and a lap belt member, one or both of the shoulder or lap belt members (18; 14) include a tubular seat belt sleeve with an inflatable member being contained within the sleeve; a source of inflation gas; a buckle assembly including a latch mechanism; a seat belt anchor having a tongue that is selectively engaged by the latch mechanism in a latched state in which the seat belt anchor is secured to the buckle assembly and is disengaged in a released state in which the seat belt anchor may be removed from the buckle assembly; the buckle has a first hollow tube that defines a first gas flow path through which an inflation gas is provided through the buckle to the tongue from the source of inflation gas, the first hollow tube having a first and second end, the first end includes a first seal surface, the second end receives the inflation gas from the source of inflation gas; the tongue includes a hollow second tube that defines a second gas flow path through which the inflation gas flows from the first gas flow path to the inflatable member, said second tube has a first and second end, the first end of the second tube includes a second seal surface to create a gas seal with the first end of the first hollow tube when the latch mechanism is in the latched state, and the second end of the tongue is in communication with an inlet of the inflatable member, characterized in that a spring, housed within said first hollow tube, biases the first end of said first hollow tube into engagement with the tongue when the latch mechanism is in the latched state to hold the first and second seal surfaces together. a shoulder belt member and a lap belt member, one or both of the shoulder or lap belt members (18; 14) include a tubular seat belt sleeve with an inflatable member being contained within the sleeve; a source of inflation gas; a buckle assembly including a latch mechanism; a seat belt anchor having a tongue that is selectively engaged by the latch mechanism in a latched state in which the seat belt anchor is secured to the buckle assembly and is disengaged in a released state in which the seat belt anchor may be removed from the buckle assembly; the buckle has a first hollow tube that defines a first gas flow path through which an inflation gas is provided through the buckle to the tongue from the source of inflation gas, the first hollow tube having a first and second end, the first end includes a first seal surface, the second end receives the inflation gas from the source of inflation gas; the tongue includes a hollow second tube that defines a second gas flow path through which the inflation gas flows from the first gas flow path to the inflatable member, said second tube has a first and second end, the first end of the second tube includes a second seal surface to create a gas seal with the first end of the first hollow tube when the latch mechanism is in the latched state, and the second end of the tongue is in communication with an inlet of the inflatable member, characterized in that a spring, housed within said first hollow tube, biases the first end of said first hollow tube into engagement with the tongue when the latch mechanism is in the latched state to hold the first and second seal surfaces together.