Abstract: A drinking bottle assembly includes a lid assembly with a lid housing having a top wall, a flap rotatably coupled to the top wall, and a gasket secured to the flap. A drink opening extends through the top wall. A rim extends above the top wall. At least one notch is located in an inner surface of the rim. The flap includes a flexible portion or extension and at least one locking lug projecting from the flexible portion. The locking lug engages the at least one notch in a closed position. The flap is rotatable from the closed position to a fully open position. The gasket is configured to seal the drink opening in the closed position.