An inflatable mailer having a liner that can be inflated at the point of use. The liner includes a series of inflatable chambers that are in fluid communication with a common channel. A controlled volume of gas is disposed in the liner. The gas is sufficient to inflate the common channel but is not sufficient to appreciably inflate the inflatable chambers. As a result, the inflatable mailer is in a relatively compact state. An apparatus for inflating the mailer. The apparatus includes a nip for moving the controlled volume of gas into the common channel; an inflation nozzle comprising a pointed needle configured to pierce the inflated common channel and introduce a second portion of gas into the liner until the liner is inflated to a desired level; and a sealing device to seal the inflated liner.