Abstract: A sleeve (1) for beverage containers (2) made of a substantially planar rigid material, such as cardboard, having side sections (6) which are foldably connected along folding creases (4) to form a sleeve having a top opening (3) for inserting a container. The sleeve has a bottom coaster (11) which is foldably connected to a bottom of one of the side sections which is supported by a strut (8) under the coaster adhesively attached at a folding tab (9) to the bottom of the coaster. An extension (7) on the coaster (11) is also provided to extend through a slit (18) in the folding strut for additional support. When the sleeve is assembled, the entire coaster (11) and strut (8) fold up into the body of the sleeve for easy storage and shipping. When the sleeve (1) contains a beverage container during use configuration, the coaster (11) covers the entire bottom of the sleeve, thereby preventing moisture from wetting or damaging a surface on which it is placed.