Abstract: Unitary beverage containers and methods of filling thereof are disclosed where the beverage container includes a main body and a filling conduit extending from the top thereof which is closed off after filling. In embodiments with a separate straw, an attaching mechanism removably attaches the distal end of the flexible straw to the top of main body and closes the aperture in the distal end. The attaching mechanism includes a short hollow bridge extending from the aperture which is broken during removal of the flexible straw to uncover the aperture prior to use. The hollow bridge is connected to a hollow chamber member which is otherwise isolated fluidly from the container volume. A concavity is provided at the top in which a mouthpiece at the distal end of the straw is received. In some preferred embodiments, the filling conduit extends from the top of the main body, and from adjacent the mouthpiece or from the mouthpiece itself.