An apparatus includes a seat flap for supporting a baby's buttocks and thighs. The seat flap has a top edge, a bottom edge having a shorter length than a length of the top edge and generally curved side edges. A first strap is joined to a first corner of the top edge for adjustably joining to an upper portion of a baby carrier. A second strap is joined to a second corner of the top edge for adjustably joining to the upper portion. Attachments adjustably join the bottom edge about a lower portion of the baby carrier, wherein the baby sits upright, the baby's legs protrude about the generally curved side edges and are supported at least ninety degrees from the lower portion.